| 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. |
