White space fix only. Translators can ignore.
Sponsored by: iXsystems
This commit is contained in:
Dru Lavigne
parent
67995497aa
commit
e3d8bc4dd2
Notes:
svn2git
2020-12-08 03:00:23 +00:00
svn path=/head/; revision=44790
1 changed files with 395 additions and 411 deletions
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@ -104,59 +104,57 @@
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</variablelist>
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<para>When referring to communication data rates, this section
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does not use the term <firstterm>baud</firstterm>. Baud refers to the
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number of electrical state transitions made in a
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period of time, while <acronym>bps</acronym> is the
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correct term to use.</para>
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||||
does not use the term <firstterm>baud</firstterm>. Baud refers
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to the number of electrical state transitions made in a period
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of time, while <acronym>bps</acronym> is the correct term to
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use.</para>
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<para>To connect a serial terminal to a &os; system, a
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serial port on the computer and the proper cable to connect to
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the serial device are needed. Users who are already familiar
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with serial hardware and cabling can safely skip this
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section.</para>
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<para>To connect a serial terminal to a &os; system, a serial port
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on the computer and the proper cable to connect to the serial
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device are needed. Users who are already familiar with serial
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hardware and cabling can safely skip this section.</para>
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<sect2 xml:id="term-cables-null">
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<title>Serial Cables and Ports</title>
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<para>There are several different kinds of serial cables. The
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two most common types are null-modem cables and standard
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<acronym>RS-232</acronym> cables. The documentation for the hardware should
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describe the type of cable required.</para>
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<acronym>RS-232</acronym> cables. The documentation for the
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hardware should describe the type of cable required.</para>
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<para>These two types of cables differ in how the wires are
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connected to the connector. Each wire represents a signal,
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with the defined signals summarized in <xref
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linkend="serialcomms-signal-names"/>. A standard serial
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cable passes all of the <acronym>RS-232C</acronym> signals
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straight through. For example, the <quote>Transmitted Data</quote> pin on
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one end of the cable goes to the <quote>Transmitted
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Data</quote> pin on the other end. This is the type of
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cable used to connect a modem to the &os; system, and is also
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appropriate for some terminals.</para>
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straight through. For example, the <quote>Transmitted
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Data</quote> pin on one end of the cable goes to the
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<quote>Transmitted Data</quote> pin on the other end. This is
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the type of cable used to connect a modem to the &os; system,
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and is also appropriate for some terminals.</para>
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<para>A null-modem cable
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switches the <quote>Transmitted Data</quote> pin of the
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connector on one end with the <quote>Received
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Data</quote> pin on the other end. The connector can be
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either a <acronym>DB-25</acronym> or a
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<para>A null-modem cable switches the <quote>Transmitted
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Data</quote> pin of the connector on one end with the
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<quote>Received Data</quote> pin on the other end. The
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connector can be either a <acronym>DB-25</acronym> or a
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<acronym>DB-9</acronym>.</para>
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<para>A null-modem cable can be constructed
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using the pin connections summarized in <xref
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linkend="nullmodem-db25"/>, <xref
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linkend="nullmodem-db9"/>, and <xref
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linkend="nullmodem-db9-25"/>. While the standard
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calls for a straight-through pin 1 to pin 1
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<quote>Protective Ground</quote> line, it is often
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omitted. Some terminals work using only pins 2, 3, and 7,
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while others require different configurations. When in doubt,
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refer to the documentation for the hardware.</para>
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<para>A null-modem cable can be constructed using the pin
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connections summarized in <xref linkend="nullmodem-db25"/>,
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<xref linkend="nullmodem-db9"/>, and <xref
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linkend="nullmodem-db9-25"/>. While the standard calls for
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a straight-through pin 1 to pin 1 <quote>Protective
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Ground</quote> line, it is often omitted. Some terminals
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work using only pins 2, 3, and 7, while others require
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different configurations. When in doubt, refer to the
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documentation for the hardware.</para>
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<indexterm>
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<primary>null-modem cable</primary>
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</indexterm>
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<table frame="none" pgwide="1" xml:id="serialcomms-signal-names">
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<table frame="none" pgwide="1"
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xml:id="serialcomms-signal-names">
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<title><acronym>RS-232C</acronym> Signal Names</title>
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<tgroup cols="2">
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@ -494,13 +492,13 @@
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constructing a cable, make sure it will fit the ports on the
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terminal and on the &os; system.</para>
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<para>Most terminals have <acronym>DB-25</acronym> ports. Personal computers may
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have <acronym>DB-25</acronym> or <acronym>DB-9</acronym>
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ports. A multiport serial card may have
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<acronym>RJ-12</acronym> or <acronym>RJ-45/</acronym> ports.
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See the documentation that accompanied the hardware for
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specifications on the kind of port or visually verify the type
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of port.</para>
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<para>Most terminals have <acronym>DB-25</acronym> ports.
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Personal computers may have <acronym>DB-25</acronym> or
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<acronym>DB-9</acronym> ports. A multiport serial card may
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have <acronym>RJ-12</acronym> or <acronym>RJ-45/</acronym>
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ports. See the documentation that accompanied the hardware
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for specifications on the kind of port or visually verify the
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type of port.</para>
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<para>In &os;, each serial port is accessed through an entry in
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<filename>/dev</filename>. There are two different kinds of
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@ -516,10 +514,10 @@
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<filename>/dev/ttyu0</filename> to refer to the terminal.
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If the terminal is on the second serial port
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(<filename>COM2</filename>), use
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<filename>/dev/ttyu1</filename>, and so forth. Generally, the call-in port is used
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for terminals. Call-in ports require that the serial line
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assert the <quote>Data Carrier Detect</quote>
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signal to work correctly.</para>
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<filename>/dev/ttyu1</filename>, and so forth. Generally,
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the call-in port is used for terminals. Call-in ports
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require that the serial line assert the <quote>Data
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Carrier Detect</quote> signal to work correctly.</para>
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</listitem>
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<listitem>
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@ -527,17 +525,17 @@
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<filename>/dev/cuau<replaceable>N</replaceable></filename>
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on &os; versions 10.x and higher and
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<filename>/dev/cuad<replaceable>N</replaceable></filename>
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on &os; versions 9.x and lower.
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Call-out ports are usually not used for terminals, but are
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used for modems. The call-out port can be used if the
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serial cable or the terminal does not support the <quote>Data Carrier Detect</quote>
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signal.</para>
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on &os; versions 9.x and lower. Call-out ports are
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usually not used for terminals, but are used for modems.
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The call-out port can be used if the serial cable or the
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terminal does not support the <quote>Data Carrier
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Detect</quote> signal.</para>
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</listitem>
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</itemizedlist>
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<para>&os; also provides initialization
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devices
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(<filename>/dev/ttyu<replaceable>N</replaceable>.init</filename> and
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<para>&os; also provides initialization devices
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(<filename>/dev/ttyu<replaceable>N</replaceable>.init</filename>
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and
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<filename>/dev/cuau<replaceable>N</replaceable>.init</filename>
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or
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<filename>/dev/cuad<replaceable>N</replaceable>.init</filename>)
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@ -553,9 +551,9 @@
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<literal>RTS/CTS</literal> signaling for flow control. The
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locking devices are used to lock flags on ports to prevent
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users or programs changing certain parameters. Refer to
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&man.termios.4;, &man.sio.4;, and &man.stty.1; for
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information on terminal settings, locking and initializing
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devices, and setting terminal options, respectively.</para>
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&man.termios.4;, &man.sio.4;, and &man.stty.1; for information
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on terminal settings, locking and initializing devices, and
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setting terminal options, respectively.</para>
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</sect2>
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<sect2 xml:id="serial-hw-config">
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@ -564,12 +562,11 @@
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<para>By default, &os; supports four serial ports which are
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commonly known as <filename>COM1</filename>,
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<filename>COM2</filename>, <filename>COM3</filename>, and
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<filename>COM4</filename>. &os; also supports
|
||||
dumb multi-port serial interface cards, such as
|
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the BocaBoard 1008 and 2016, as well as more intelligent
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||||
multi-port cards such as those made by Digiboard. However,
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||||
the default kernel only looks for the
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standard <filename>COM</filename> ports.</para>
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||||
<filename>COM4</filename>. &os; also supports dumb multi-port
|
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serial interface cards, such as the BocaBoard 1008 and 2016,
|
||||
as well as more intelligent multi-port cards such as those
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||||
made by Digiboard. However, the default kernel only looks for
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the standard <filename>COM</filename> ports.</para>
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<para>To see if the system recognizes the serial ports, look for
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system boot messages that start with
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@ -577,17 +574,18 @@
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<screen>&prompt.root; <userinput>grep uart /var/run/dmesg.boot</userinput></screen>
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<para>If the system does not recognize all of the needed serial ports,
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additional entries can be added to
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<para>If the system does not recognize all of the needed serial
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ports, additional entries can be added to
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<filename>/boot/device.hints</filename>. This file already
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contains <literal>hint.uart.0.*</literal> entries for
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<filename>COM1</filename> and <literal>hint.uart.1.*</literal> entries
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||||
for <filename>COM2</filename>. When adding a port entry for
|
||||
<filename>COM3</filename> use
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||||
<literal>0x3E8</literal>, and for <filename>COM4</filename> use
|
||||
<literal>0x2E8</literal>. Common <acronym>IRQ</acronym> addresses
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||||
are <literal>5</literal> for <filename>COM3</filename> and
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<literal>9</literal> for <filename>COM4</filename>.</para>
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||||
<filename>COM1</filename> and <literal>hint.uart.1.*</literal>
|
||||
entries for <filename>COM2</filename>. When adding a port
|
||||
entry for <filename>COM3</filename> use
|
||||
<literal>0x3E8</literal>, and for <filename>COM4</filename>
|
||||
use <literal>0x2E8</literal>. Common <acronym>IRQ</acronym>
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||||
addresses are <literal>5</literal> for
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||||
<filename>COM3</filename> and <literal>9</literal> for
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||||
<filename>COM4</filename>.</para>
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||||
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<indexterm><primary><filename>ttyu</filename></primary></indexterm>
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<indexterm><primary><filename>cuau</filename></primary></indexterm>
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@ -599,17 +597,16 @@
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<screen>&prompt.root; <userinput>stty -a -f /dev/<replaceable>ttyu1</replaceable></userinput></screen>
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||||
<para>System-wide initialization of serial devices is
|
||||
controlled by <filename>/etc/rc.d/serial</filename>. This
|
||||
file affects the default settings of serial devices. To
|
||||
change the settings for a device, use <command>stty</command>.
|
||||
By default, the changed settings
|
||||
are in effect until the device is closed and when the device is
|
||||
reopened, it goes back to the default set. To permanently
|
||||
change the default set, open and adjust the settings of the
|
||||
initialization device. For example, to turn on
|
||||
<option>CLOCAL</option> mode, 8 bit communication, and
|
||||
<option>XON/XOFF</option> flow control for
|
||||
<para>System-wide initialization of serial devices is controlled
|
||||
by <filename>/etc/rc.d/serial</filename>. This file affects
|
||||
the default settings of serial devices. To change the
|
||||
settings for a device, use <command>stty</command>. By
|
||||
default, the changed settings are in effect until the device
|
||||
is closed and when the device is reopened, it goes back to the
|
||||
default set. To permanently change the default set, open and
|
||||
adjust the settings of the initialization device. For
|
||||
example, to turn on <option>CLOCAL</option> mode, 8 bit
|
||||
communication, and <option>XON/XOFF</option> flow control for
|
||||
<filename>ttyu5</filename>, type:</para>
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||||
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<screen>&prompt.root; <userinput>stty -f /dev/ttyu5.init clocal cs8 ixon ixoff</userinput></screen>
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@ -620,15 +617,15 @@
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</indexterm>
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||||
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<para>To prevent certain settings from being changed by an
|
||||
application, make adjustments to the locking
|
||||
device. For example, to lock the speed of
|
||||
<filename>ttyu5</filename> to 57600 bps, type:</para>
|
||||
application, make adjustments to the locking device. For
|
||||
example, to lock the speed of <filename>ttyu5</filename> to
|
||||
57600 bps, type:</para>
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||||
|
||||
<screen>&prompt.root; <userinput>stty -f /dev/ttyu5.lock 57600</userinput></screen>
|
||||
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<para>Now, any application that opens
|
||||
<filename>ttyu5</filename> and tries to change the speed
|
||||
of the port will be stuck with 57600 bps.</para>
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||||
<para>Now, any application that opens <filename>ttyu5</filename>
|
||||
and tries to change the speed of the port will be stuck with
|
||||
57600 bps.</para>
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||||
</sect2>
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</sect1>
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@ -761,10 +758,10 @@
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<title>Terminal Configuration</title>
|
||||
|
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<para>This section describes how to configure a &os; system to
|
||||
enable a login session on a serial terminal. It assumes that the
|
||||
system recognizes the serial port to which the
|
||||
terminal is connected and that the terminal is
|
||||
connected with the correct cable.</para>
|
||||
enable a login session on a serial terminal. It assumes that
|
||||
the system recognizes the serial port to which the terminal is
|
||||
connected and that the terminal is connected with the correct
|
||||
cable.</para>
|
||||
|
||||
<para>In &os;, <command>init</command> reads
|
||||
<filename>/etc/ttys</filename> and starts a
|
||||
|
|
@ -774,17 +771,17 @@
|
|||
program. The ports on the &os; system which allow logins are
|
||||
listed in <filename>/etc/ttys</filename>. For example, the
|
||||
first virtual console, <filename>ttyv0</filename>, has an
|
||||
entry in this file, allowing logins on the console. This
|
||||
file also contains entries for the other virtual consoles,
|
||||
serial ports, and pseudo-ttys. For a hardwired terminal,
|
||||
the serial port's <filename>/dev</filename> entry is listed
|
||||
without the <literal>/dev</literal> part. For example,
|
||||
entry in this file, allowing logins on the console. This file
|
||||
also contains entries for the other virtual consoles, serial
|
||||
ports, and pseudo-ttys. For a hardwired terminal, the serial
|
||||
port's <filename>/dev</filename> entry is listed without the
|
||||
<literal>/dev</literal> part. For example,
|
||||
<filename>/dev/ttyv0</filename> is listed as
|
||||
<literal>ttyv0</literal>.</para>
|
||||
|
||||
<para>The default
|
||||
<filename>/etc/ttys</filename> configures support for the first
|
||||
four serial ports, <filename>ttyu0</filename> through
|
||||
<para>The default <filename>/etc/ttys</filename> configures
|
||||
support for the first four serial ports,
|
||||
<filename>ttyu0</filename> through
|
||||
<filename>ttyu3</filename>:</para>
|
||||
|
||||
<programlisting>ttyu0 "/usr/libexec/getty std.9600" dialup off secure
|
||||
|
|
@ -792,22 +789,20 @@ ttyu1 "/usr/libexec/getty std.9600" dialup off secure
|
|||
ttyu2 "/usr/libexec/getty std.9600" dialup off secure
|
||||
ttyu3 "/usr/libexec/getty std.9600" dialup off secure</programlisting>
|
||||
|
||||
<para>When attaching a terminal to
|
||||
one of those ports, modify the default entry to set the
|
||||
required speed and terminal type, to turn the device
|
||||
<literal>on</literal> and, if needed, to change the port's
|
||||
<literal>secure</literal> setting. If the terminal is
|
||||
connected to another port, add an entry for the port.</para>
|
||||
<para>When attaching a terminal to one of those ports, modify
|
||||
the default entry to set the required speed and terminal type,
|
||||
to turn the device <literal>on</literal> and, if needed, to
|
||||
change the port's <literal>secure</literal> setting. If the
|
||||
terminal is connected to another port, add an entry for the
|
||||
port.</para>
|
||||
|
||||
<para><xref linkend="ex-etc-ttys"/> configures two
|
||||
terminals in <filename>/etc/ttys</filename>. The first
|
||||
entry configures a Wyse-50
|
||||
connected to <filename>COM2</filename>. The second entry
|
||||
configures an old computer running
|
||||
<application>Procomm</application> terminal software
|
||||
emulating a VT-100 terminal. The computer is connected
|
||||
to the sixth serial port on
|
||||
a multi-port serial card.</para>
|
||||
<para><xref linkend="ex-etc-ttys"/> configures two terminals in
|
||||
<filename>/etc/ttys</filename>. The first entry configures a
|
||||
Wyse-50 connected to <filename>COM2</filename>. The second
|
||||
entry configures an old computer running
|
||||
<application>Procomm</application> terminal software emulating
|
||||
a VT-100 terminal. The computer is connected to the sixth
|
||||
serial port on a multi-port serial card.</para>
|
||||
|
||||
<example xml:id="ex-etc-ttys">
|
||||
<title>Configuring Terminal Entries</title>
|
||||
|
|
@ -817,83 +812,81 @@ ttyu5 "/usr/libexec/getty std.19200" vt100 on insecure</programlisting>
|
|||
|
||||
<calloutlist>
|
||||
<callout arearefs="co-ttys-line1col1">
|
||||
<para>The first field specifies the device name of
|
||||
the serial terminal.</para>
|
||||
<para>The first field specifies the device name of the
|
||||
serial terminal.</para>
|
||||
</callout>
|
||||
|
||||
<callout arearefs="co-ttys-line1col2">
|
||||
<para>The second field tells
|
||||
<command>getty</command> to initialize and open the
|
||||
line, set the line speed, prompt for a user name, and
|
||||
then execute the <command>login</command> program. The optional
|
||||
<para>The second field tells <command>getty</command> to
|
||||
initialize and open the line, set the line speed, prompt
|
||||
for a user name, and then execute the
|
||||
<command>login</command> program. The optional
|
||||
<firstterm>getty type</firstterm> configures
|
||||
characteristics on the terminal line, like
|
||||
<acronym>bps</acronym> rate and parity. The available
|
||||
getty types are listed in
|
||||
<filename>/etc/gettytab</filename>. In
|
||||
almost all cases, the getty types that start with
|
||||
<literal>std</literal> will work for hardwired
|
||||
terminals as these entries ignore parity. There is
|
||||
a <literal>std</literal> entry for each
|
||||
<acronym>bps</acronym> rate from 110 to 115200. Refer to
|
||||
&man.gettytab.5; for more information.</para>
|
||||
<filename>/etc/gettytab</filename>. In almost all
|
||||
cases, the getty types that start with
|
||||
<literal>std</literal> will work for hardwired terminals
|
||||
as these entries ignore parity. There is a
|
||||
<literal>std</literal> entry for each
|
||||
<acronym>bps</acronym> rate from 110 to 115200. Refer
|
||||
to &man.gettytab.5; for more information.</para>
|
||||
|
||||
<para>When setting the getty
|
||||
type, make sure to match
|
||||
the communications settings used by the terminal. For
|
||||
this example, the Wyse-50 uses no parity and
|
||||
connects at 38400 bps. The computer uses no
|
||||
parity and connects at 19200 bps.</para>
|
||||
<para>When setting the getty type, make sure to match the
|
||||
communications settings used by the terminal. For this
|
||||
example, the Wyse-50 uses no parity and connects at
|
||||
38400 bps. The computer uses no parity and
|
||||
connects at 19200 bps.</para>
|
||||
</callout>
|
||||
|
||||
<callout arearefs="co-ttys-line1col3">
|
||||
<para>The third field is the type of terminal. For dial-up ports,
|
||||
<literal>unknown</literal> or
|
||||
<literal>dialup</literal> is typically used since
|
||||
users may dial up with practically any type of
|
||||
terminal or software. Since the terminal type does
|
||||
not change for hardwired terminals, a real terminal
|
||||
type from <filename>/etc/termcap</filename> can be specified.
|
||||
For this example, the Wyse-50 uses the real
|
||||
terminal type while the computer running
|
||||
<application>Procomm</application> is set to
|
||||
emulate a VT-100.</para>
|
||||
<para>The third field is the type of terminal. For
|
||||
dial-up ports, <literal>unknown</literal> or
|
||||
<literal>dialup</literal> is typically used since users
|
||||
may dial up with practically any type of terminal or
|
||||
software. Since the terminal type does not change for
|
||||
hardwired terminals, a real terminal type from
|
||||
<filename>/etc/termcap</filename> can be specified. For
|
||||
this example, the Wyse-50 uses the real terminal type
|
||||
while the computer running
|
||||
<application>Procomm</application> is set to emulate a
|
||||
VT-100.</para>
|
||||
</callout>
|
||||
|
||||
<callout arearefs="co-ttys-line1col4">
|
||||
<para>The fourth field specifies if the port should be
|
||||
enabled. To enable logins on this port, this
|
||||
field must be set to <literal>on</literal>.</para>
|
||||
enabled. To enable logins on this port, this field must
|
||||
be set to <literal>on</literal>.</para>
|
||||
</callout>
|
||||
|
||||
<callout arearefs="co-ttys-line1col5">
|
||||
<para>The final field is used to specify whether the
|
||||
port is secure. Marking a port as
|
||||
<literal>secure</literal> means that it is trusted
|
||||
enough to allow <systemitem
|
||||
<para>The final field is used to specify whether the port
|
||||
is secure. Marking a port as <literal>secure</literal>
|
||||
means that it is trusted enough to allow <systemitem
|
||||
class="username">root</systemitem> to login from that
|
||||
port. Insecure ports do not allow <systemitem
|
||||
class="username">root</systemitem> logins. On an
|
||||
insecure port, users must login from unprivileged
|
||||
accounts and then use <command>su</command> or a similar
|
||||
mechanism to gain superuser privileges, as described
|
||||
in <xref linkend="users-superuser"/>. For security reasons,
|
||||
it is recommended to change this setting to
|
||||
mechanism to gain superuser privileges, as described in
|
||||
<xref linkend="users-superuser"/>. For security
|
||||
reasons, it is recommended to change this setting to
|
||||
<literal>insecure</literal>.</para>
|
||||
</callout>
|
||||
</calloutlist>
|
||||
</example>
|
||||
|
||||
<para>After making any changes to
|
||||
<filename>/etc/ttys</filename>, send a SIGHUP (hangup)
|
||||
signal to the <command>init</command> process to force it to
|
||||
re-read its configuration file:</para>
|
||||
<filename>/etc/ttys</filename>, send a SIGHUP (hangup) signal
|
||||
to the <command>init</command> process to force it to re-read
|
||||
its configuration file:</para>
|
||||
|
||||
<screen>&prompt.root; <userinput>kill -HUP 1</userinput></screen>
|
||||
|
||||
<para>Since <command>init</command> is always the first process
|
||||
run on a system, it always has a process
|
||||
<acronym>ID</acronym> of <literal>1</literal>.</para>
|
||||
run on a system, it always has a process <acronym>ID</acronym>
|
||||
of <literal>1</literal>.</para>
|
||||
|
||||
<para>If everything is set up correctly, all cables are in
|
||||
place, and the terminals are powered up, a
|
||||
|
|
@ -916,8 +909,8 @@ ttyu5 "/usr/libexec/getty std.19200" vt100 on insecure</programlisting>
|
|||
emulation software on the correct serial port.</para>
|
||||
|
||||
<para>Make sure the cable is connected firmly to both the
|
||||
terminal and the &os; computer. Make sure it is the
|
||||
right kind of cable.</para>
|
||||
terminal and the &os; computer. Make sure it is the right
|
||||
kind of cable.</para>
|
||||
|
||||
<para>Make sure the terminal and &os; agree on the
|
||||
<acronym>bps</acronym> rate and parity settings. For a video
|
||||
|
|
@ -926,11 +919,11 @@ ttyu5 "/usr/libexec/getty std.19200" vt100 on insecure</programlisting>
|
|||
sure paper and ink are in good supply.</para>
|
||||
|
||||
<para>Use <command>ps</command> to make sure that a
|
||||
<command>getty</command> process is
|
||||
running and serving the terminal. For example,
|
||||
the following listing shows that a <command>getty</command> is
|
||||
running on the second serial port, <filename>ttyu1</filename>,
|
||||
and is using the <literal>std.38400</literal> entry in
|
||||
<command>getty</command> process is running and serving the
|
||||
terminal. For example, the following listing shows that a
|
||||
<command>getty</command> is running on the second serial port,
|
||||
<filename>ttyu1</filename>, and is using the
|
||||
<literal>std.38400</literal> entry in
|
||||
<filename>/etc/gettytab</filename>:</para>
|
||||
|
||||
<screen>&prompt.root; <userinput>ps -axww|grep ttyu</userinput>
|
||||
|
|
@ -996,37 +989,40 @@ ttyu5 "/usr/libexec/getty std.19200" vt100 on insecure</programlisting>
|
|||
|
||||
<indexterm><primary>dial-in service</primary></indexterm>
|
||||
|
||||
<para>Configuring a &os; system for dial-in service is similar
|
||||
to configuring terminals, except that modems are used instead of
|
||||
<para>Configuring a &os; system for dial-in service is similar to
|
||||
configuring terminals, except that modems are used instead of
|
||||
terminal devices. &os; supports both external and internal
|
||||
modems.</para>
|
||||
|
||||
<para>External modems are more convenient because
|
||||
they often can be configured via parameters
|
||||
stored in non-volatile <acronym>RAM</acronym> and they usually provide lighted
|
||||
indicators that display the state of important <acronym>RS-232</acronym> signals,
|
||||
indicating whether the modem is operating properly.</para>
|
||||
<para>External modems are more convenient because they often can
|
||||
be configured via parameters stored in non-volatile
|
||||
<acronym>RAM</acronym> and they usually provide lighted
|
||||
indicators that display the state of important
|
||||
<acronym>RS-232</acronym> signals, indicating whether the modem
|
||||
is operating properly.</para>
|
||||
|
||||
<para>Internal modems usually lack non-volatile <acronym>RAM</acronym>, so their
|
||||
configuration may be limited to setting <acronym>DIP</acronym> switches. If the
|
||||
internal modem has any signal indicator lights, they are
|
||||
difficult to view when the system's cover is in place.</para>
|
||||
<para>Internal modems usually lack non-volatile
|
||||
<acronym>RAM</acronym>, so their configuration may be limited to
|
||||
setting <acronym>DIP</acronym> switches. If the internal modem
|
||||
has any signal indicator lights, they are difficult to view when
|
||||
the system's cover is in place.</para>
|
||||
|
||||
<indexterm><primary>modem</primary></indexterm>
|
||||
|
||||
<para>When using an external modem, a proper cable is needed. A
|
||||
standard <acronym>RS-232C</acronym> serial cable should suffice.</para>
|
||||
standard <acronym>RS-232C</acronym> serial cable should
|
||||
suffice.</para>
|
||||
|
||||
<para>&os; needs the <acronym>RTS</acronym> and
|
||||
<acronym>CTS</acronym> signals for flow control at speeds
|
||||
above 2400 bps, the <acronym>CD</acronym> signal to
|
||||
detect when a call has been answered or the line has been hung
|
||||
up, and the <acronym>DTR</acronym> signal to reset the modem
|
||||
after a session is complete. Some cables are wired without all
|
||||
of the needed signals, so if a login session does not go away
|
||||
when the line hangs up, there may be a problem with the
|
||||
cable. Refer to <xref linkend="term-cables-null"/> for more
|
||||
information about these signals.</para>
|
||||
<acronym>CTS</acronym> signals for flow control at speeds above
|
||||
2400 bps, the <acronym>CD</acronym> signal to detect when a
|
||||
call has been answered or the line has been hung up, and the
|
||||
<acronym>DTR</acronym> signal to reset the modem after a session
|
||||
is complete. Some cables are wired without all of the needed
|
||||
signals, so if a login session does not go away when the line
|
||||
hangs up, there may be a problem with the cable. Refer to <xref
|
||||
linkend="term-cables-null"/> for more information about these
|
||||
signals.</para>
|
||||
|
||||
<para>Like other &unix;-like operating systems, &os; uses the
|
||||
hardware signals to find out when a call has been answered or a
|
||||
|
|
@ -1037,21 +1033,21 @@ ttyu5 "/usr/libexec/getty std.19200" vt100 on insecure</programlisting>
|
|||
<para>&os; supports the <acronym>NS8250</acronym>,
|
||||
<acronym>NS16450</acronym>, <acronym>NS16550</acronym>, and
|
||||
<acronym>NS16550A</acronym>-based <acronym>RS-232C</acronym>
|
||||
(<acronym>CCITT</acronym> V.24) communications
|
||||
interfaces. The 8250 and 16450 devices have single-character
|
||||
buffers. The 16550 device provides a 16-character buffer,
|
||||
which allows for better system performance. Bugs in plain
|
||||
16550 devices prevent the use of the 16-character buffer, so use
|
||||
16550A devices if possible. Because single-character-buffer
|
||||
devices require more work by the operating system than the
|
||||
16-character-buffer devices, 16550A-based serial interface
|
||||
cards are preferred. If the system has many active serial
|
||||
ports or will have a heavy load, 16550A-based cards are better
|
||||
for low-error-rate communications.</para>
|
||||
(<acronym>CCITT</acronym> V.24) communications interfaces. The
|
||||
8250 and 16450 devices have single-character buffers. The 16550
|
||||
device provides a 16-character buffer, which allows for better
|
||||
system performance. Bugs in plain 16550 devices prevent the use
|
||||
of the 16-character buffer, so use 16550A devices if possible.
|
||||
Because single-character-buffer devices require more work by the
|
||||
operating system than the 16-character-buffer devices,
|
||||
16550A-based serial interface cards are preferred. If the
|
||||
system has many active serial ports or will have a heavy load,
|
||||
16550A-based cards are better for low-error-rate
|
||||
communications.</para>
|
||||
|
||||
<para>The rest of this section demonstrates how to configure a
|
||||
modem to receive incoming connections, how to communicate
|
||||
with the modem, and offers some troubleshooting tips.</para>
|
||||
modem to receive incoming connections, how to communicate with
|
||||
the modem, and offers some troubleshooting tips.</para>
|
||||
|
||||
<sect2 xml:id="dialup-ttys">
|
||||
<title>Modem Configuration</title>
|
||||
|
|
@ -1060,77 +1056,70 @@ ttyu5 "/usr/libexec/getty std.19200" vt100 on insecure</programlisting>
|
|||
<para>As with terminals, <command>init</command> spawns a
|
||||
<command>getty</command> process for each configured serial
|
||||
port used for dial-in connections. When a user dials the
|
||||
modem's line and the modems connect,
|
||||
the <quote>Carrier Detect</quote> signal is reported by
|
||||
the modem. The kernel notices that the carrier has been
|
||||
detected and instructs <command>getty</command> to open the
|
||||
port and display a
|
||||
modem's line and the modems connect, the <quote>Carrier
|
||||
Detect</quote> signal is reported by the modem. The kernel
|
||||
notices that the carrier has been detected and instructs
|
||||
<command>getty</command> to open the port and display a
|
||||
<prompt>login:</prompt> prompt at the specified initial line
|
||||
speed. In a typical configuration, if garbage characters are
|
||||
received, usually due to the modem's connection speed
|
||||
being different than the configured speed,
|
||||
<command>getty</command> tries adjusting the line speeds until
|
||||
it receives reasonable characters. After the user enters their login name,
|
||||
<command>getty</command> executes
|
||||
<command>login</command>, which completes the login process
|
||||
by asking for the user's password and then starting the user's
|
||||
shell.</para>
|
||||
received, usually due to the modem's connection speed being
|
||||
different than the configured speed, <command>getty</command>
|
||||
tries adjusting the line speeds until it receives reasonable
|
||||
characters. After the user enters their login name,
|
||||
<command>getty</command> executes <command>login</command>,
|
||||
which completes the login process by asking for the user's
|
||||
password and then starting the user's shell.</para>
|
||||
|
||||
<indexterm>
|
||||
<primary><command>/usr/bin/login</command></primary>
|
||||
</indexterm>
|
||||
|
||||
<para>There are two schools of thought regarding dial-up modems.
|
||||
One confiuration method is to set the modems and
|
||||
systems so that no matter at what speed a remote user dials
|
||||
in, the dial-in <acronym>RS-232</acronym>
|
||||
interface runs at a
|
||||
locked speed. The benefit of this configuration is that the
|
||||
remote user always sees a system login prompt immediately.
|
||||
The downside is that the system does not know what a user's
|
||||
true data rate is, so full-screen programs like
|
||||
One confiuration method is to set the modems and systems so
|
||||
that no matter at what speed a remote user dials in, the
|
||||
dial-in <acronym>RS-232</acronym> interface runs at a locked
|
||||
speed. The benefit of this configuration is that the remote
|
||||
user always sees a system login prompt immediately. The
|
||||
downside is that the system does not know what a user's true
|
||||
data rate is, so full-screen programs like
|
||||
<application>Emacs</application> will not adjust their
|
||||
screen-painting methods to make their response better for
|
||||
slower connections.</para>
|
||||
|
||||
<para>The second method is to configure the <acronym>RS-232</acronym> interface
|
||||
to vary its speed based on the remote user's connection speed.
|
||||
Because
|
||||
<para>The second method is to configure the
|
||||
<acronym>RS-232</acronym> interface to vary its speed based on
|
||||
the remote user's connection speed. Because
|
||||
<command>getty</command> does not understand any particular
|
||||
modem's connection speed reporting, it
|
||||
gives a <prompt>login:</prompt> message at an initial speed
|
||||
and watches the characters that come back in response. If the
|
||||
user sees junk, they should press
|
||||
<keycap>Enter</keycap> until they see a recognizable prompt.
|
||||
If the data rates do not match, <command>getty</command> sees
|
||||
anything the user types as junk, tries
|
||||
the next speed, and gives the <prompt>login:</prompt> prompt
|
||||
again. This procedure normally only takes a keystroke or two
|
||||
before the user sees a good prompt. This login sequence does
|
||||
not look as clean as the locked-speed method,
|
||||
but a user on a low-speed connection should receive better
|
||||
interactive response from full-screen programs.</para>
|
||||
modem's connection speed reporting, it gives a
|
||||
<prompt>login:</prompt> message at an initial speed and
|
||||
watches the characters that come back in response. If the
|
||||
user sees junk, they should press <keycap>Enter</keycap> until
|
||||
they see a recognizable prompt. If the data rates do not
|
||||
match, <command>getty</command> sees anything the user types
|
||||
as junk, tries the next speed, and gives the
|
||||
<prompt>login:</prompt> prompt again. This procedure normally
|
||||
only takes a keystroke or two before the user sees a good
|
||||
prompt. This login sequence does not look as clean as the
|
||||
locked-speed method, but a user on a low-speed connection
|
||||
should receive better interactive response from full-screen
|
||||
programs.</para>
|
||||
|
||||
<para>When locking a modem's data communications rate at a
|
||||
particular speed, no changes to
|
||||
<filename>/etc/gettytab</filename> should be needed.
|
||||
However, for a matching-speed
|
||||
configuration, additional entries may be required in
|
||||
order to define the speeds to use
|
||||
for the modem. This example configures a
|
||||
14.4 Kbps modem with a top interface speed of
|
||||
19.2 Kbps using 8-bit, no parity connections. It
|
||||
configures <command>getty</command> to start the
|
||||
communications rate for a V.32bis connection at
|
||||
19.2 Kbps, then cycles
|
||||
through 9600 bps, 2400 bps,
|
||||
1200 bps, 300 bps, and back to 19.2 Kbps.
|
||||
Communications rate cycling is implemented with the
|
||||
<literal>nx=</literal> (next table)
|
||||
capability. Each line uses a
|
||||
<literal>tc=</literal> (table continuation)
|
||||
entry to pick up the rest of the
|
||||
settings for a particular data rate.</para>
|
||||
<filename>/etc/gettytab</filename> should be needed. However,
|
||||
for a matching-speed configuration, additional entries may be
|
||||
required in order to define the speeds to use for the modem.
|
||||
This example configures a 14.4 Kbps modem with a top
|
||||
interface speed of 19.2 Kbps using 8-bit, no parity
|
||||
connections. It configures <command>getty</command> to start
|
||||
the communications rate for a V.32bis connection at
|
||||
19.2 Kbps, then cycles through 9600 bps,
|
||||
2400 bps, 1200 bps, 300 bps, and back to
|
||||
19.2 Kbps. Communications rate cycling is implemented
|
||||
with the <literal>nx=</literal> (next table) capability. Each
|
||||
line uses a <literal>tc=</literal> (table continuation) entry
|
||||
to pick up the rest of the settings for a particular data
|
||||
rate.</para>
|
||||
|
||||
<programlisting>#
|
||||
# Additions for a V.32bis Modem
|
||||
|
|
@ -1165,51 +1154,48 @@ vp|VH9600|Very High Speed Modem at 9600,8-bit:\
|
|||
vq|VH57600|Very High Speed Modem at 57600,8-bit:\
|
||||
:nx=VH9600:tc=std.57600:</programlisting>
|
||||
|
||||
<para>For a slow <acronym>CPU</acronym> or a heavily loaded system without
|
||||
16550A-based serial ports, this configuration may produce
|
||||
<errorname>sio</errorname>
|
||||
<para>For a slow <acronym>CPU</acronym> or a heavily loaded
|
||||
system without 16550A-based serial ports, this configuration
|
||||
may produce <errorname>sio</errorname>
|
||||
<quote>silo</quote> errors at 57.6 Kbps.</para>
|
||||
|
||||
<indexterm>
|
||||
<primary><filename>/etc/ttys</filename></primary>
|
||||
</indexterm>
|
||||
|
||||
<para>The configuration of <filename>/etc/ttys</filename>
|
||||
is similar to <xref linkend="ex-etc-ttys"/>,
|
||||
but a different
|
||||
<para>The configuration of <filename>/etc/ttys</filename> is
|
||||
similar to <xref linkend="ex-etc-ttys"/>, but a different
|
||||
argument is passed to <command>getty</command> and
|
||||
<literal>dialup</literal> is used for the terminal type.
|
||||
Replace
|
||||
<replaceable>xxx</replaceable> with the process
|
||||
Replace <replaceable>xxx</replaceable> with the process
|
||||
<command>init</command> will run on the device:</para>
|
||||
|
||||
<programlisting>ttyu0 "/usr/libexec/getty <replaceable>xxx</replaceable>" dialup on</programlisting>
|
||||
|
||||
<para>The <literal>dialup</literal> terminal type can be
|
||||
changed. For example, setting <literal>vt102</literal> as the
|
||||
default terminal type allows users to use <acronym>VT102</acronym> emulation on
|
||||
their remote systems.</para>
|
||||
default terminal type allows users to use
|
||||
<acronym>VT102</acronym> emulation on their remote
|
||||
systems.</para>
|
||||
|
||||
<para>For a locked-speed configuration, specify the speed with
|
||||
a valid type listed in
|
||||
<filename>/etc/gettytab</filename>.
|
||||
a valid type listed in <filename>/etc/gettytab</filename>.
|
||||
This example is for a modem whose port speed is locked at
|
||||
19.2 Kbps:</para>
|
||||
|
||||
<programlisting>ttyu0 "/usr/libexec/getty std.<replaceable>19200</replaceable>" dialup on</programlisting>
|
||||
|
||||
<para>In a matching-speed configuration, the
|
||||
entry needs to reference the
|
||||
appropriate beginning <quote>auto-baud</quote> entry in
|
||||
<filename>/etc/gettytab</filename>. To continue the example
|
||||
for a matching-speed modem that
|
||||
starts at 19.2 Kbps, use this entry:</para>
|
||||
<para>In a matching-speed configuration, the entry needs to
|
||||
reference the appropriate beginning <quote>auto-baud</quote>
|
||||
entry in <filename>/etc/gettytab</filename>. To continue the
|
||||
example for a matching-speed modem that starts at
|
||||
19.2 Kbps, use this entry:</para>
|
||||
|
||||
<programlisting>ttyu0 "/usr/libexec/getty V19200" dialup on</programlisting>
|
||||
|
||||
<para>After editing <filename>/etc/ttys</filename>, wait until
|
||||
the modem is properly configured and
|
||||
connected before signaling <command>init</command>:</para>
|
||||
the modem is properly configured and connected before
|
||||
signaling <command>init</command>:</para>
|
||||
|
||||
<screen>&prompt.root; <userinput>kill -HUP 1</userinput></screen>
|
||||
|
||||
|
|
@ -1219,14 +1205,12 @@ vq|VH57600|Very High Speed Modem at 57600,8-bit:\
|
|||
</indexterm>
|
||||
|
||||
<para>High-speed modems, like <acronym>V.32</acronym>,
|
||||
<acronym>V.32bis</acronym>, and <acronym>V.34</acronym> modems,
|
||||
use hardware (<literal>RTS/CTS</literal>) flow
|
||||
control. Use <command>stty</command> to set the
|
||||
hardware flow control flag for the modem
|
||||
port. This example sets the
|
||||
<varname>crtscts</varname> flag on
|
||||
<filename>COM2</filename>'s dial-in and dial-out
|
||||
initialization devices:</para>
|
||||
<acronym>V.32bis</acronym>, and <acronym>V.34</acronym>
|
||||
modems, use hardware (<literal>RTS/CTS</literal>) flow
|
||||
control. Use <command>stty</command> to set the hardware flow
|
||||
control flag for the modem port. This example sets the
|
||||
<varname>crtscts</varname> flag on <filename>COM2</filename>'s
|
||||
dial-in and dial-out initialization devices:</para>
|
||||
|
||||
<screen>&prompt.root; <userinput>stty -f /dev/ttyu1.init crtscts</userinput>
|
||||
&prompt.root; <userinput>stty -f /dev/cuau1.init crtscts</userinput></screen>
|
||||
|
|
@ -1365,10 +1349,10 @@ AT&B2&W</programlisting>
|
|||
modem's current operating parameters in a somewhat
|
||||
human-readable fashion. On the &usrobotics; &sportster;
|
||||
14,400 external modem, <command>ATI5</command> displays the
|
||||
settings that are stored in the non-volatile RAM. To see
|
||||
the true operating parameters of the modem, as influenced by
|
||||
the modem's DIP switch settings, use <command>ATZ</command>
|
||||
and then <command>ATI4</command>.</para>
|
||||
settings that are stored in the non-volatile RAM. To see the
|
||||
true operating parameters of the modem, as influenced by the
|
||||
modem's DIP switch settings, use <command>ATZ</command> and
|
||||
then <command>ATI4</command>.</para>
|
||||
|
||||
<para>For a different brand of modem, check the modem's manual
|
||||
to see how to double-check the modem's configuration
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue