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Diffstat (limited to 'Documentation/modems-with-agetty.txt')
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diff --git a/Documentation/modems-with-agetty.txt b/Documentation/modems-with-agetty.txt new file mode 100644 index 0000000..44a611e --- /dev/null +++ b/Documentation/modems-with-agetty.txt @@ -0,0 +1,76 @@ +25/10/95 Peter Orbaek <poe@daimi.aau.dk> + +Some notes for using agetty with modems + +Using a comms program to initialize the modem +--------------------------------------------- + +* Use kermit or minicom to initialize the modem to + + - be entirely quiet. + - don't do local echo in command mode. + - turn on DCD (carrier detect) only when there is a connection going. + - enable auto-answer. + - keep a constant computer/modem bitrate at all times. + - optionally save this setup as the modem startup configuration. + +* Run agetty on the appropriate ttySn port with the arguments: + * -w to wait for a CR or LF before writing the /etc/issue message + * computer/modem bitrate + * the tty name. + +Example from my modem setup, an old 2400 bps SupraModem using Hayes standard +AT commands. + +Initialize modem using kermit with the commands + + AT E0 Q1 &D2 &C1 S0=1 &W0 + +to + - turn off local echo from modem when in command mode (E0). + - disable all result codes from modem (Q1). + - make an on/off transition on the DTR line make the modem + disconnect and go into command mode (&D2). + - make the computer/modem DCD line track the modem/modem + carrier detect signal, i.e. no connection means no + carrier detect signal to the computer (&C1). + - enable auto-answer after the first ring (S0=1). + - store the configuration as the start configuration (&W0). + +The commands on your modem to achieve the same setup may vary, especially +the &D2 and &C1 commands may not be entirely standard. + +Exit kermit/minicom. + +Put the command + + /sbin/agetty -w 2400 ttyS1 + +in the command field of the appropriate line in /etc/inittab to start +agetty on /dev/ttyS1 with a 2400 bps speed between modem and computer. + +Initializing the modem with agetty +---------------------------------- + +Use the agetty -I command line option to specify a modem init string, like +for the same setup as above, use the following agetty command in your +/etc/inittab. + + /sbin/agetty -w -I 'ATE0Q1&D2&C1S0=1\015' 2400 ttyS1 + +The final \015 is an octal coding of the carriage return character +ending the command string. + +If you're using simpleinit (part of this package) instead of the SYSV +compatible init (you're most likely using the SYSV one!) then you must +remove the single quotes from the command line above. + +Note that the &W0 command was not used here since the modem will be +initialized each time agetty starts. + +With a V.34 (28.8 kbps) modem try starting with a command like: + + /sbin/agetty -w -I 'ATE0Q1&D2&C1S0=1\015' 115200 ttyS1 + +Note that agetty supports the higher (>9600 bps) serial speeds +directly, there's no need to use setserial to use the higher speeds. |