mroddy@enmasse.UUCP (Mark Roddy) (06/25/85)
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I'm faced with a design question on implementing autodial for low speed
synch modems (i.e. 4800 bps.)
The only synchronous modem I've got a spec for is a UDS 4800 model.
Dialout is accomplished by:
1) driving pin 12 high;
2) driving DTR high;
3) waiting a specified time;
4) raising pin 25 high for 3.5 seconds;
5) providing high and low pulses on pin 25 corresponding to bell
standard pulse dial signals.
The questions are:
1) does anyone manufacture synchronous modems with some analogy to the
Hayes protocol for async dial out?
2) Is UDS's method done by anyone else? (i.e. is this a standard?)
3) If the answer to question 2 is no, then is there a standard?
4) If the answer to 2 and 3 is no, then what dialout interface do
other netlanders provide for their intelligent comm boards?
5) In fact, even if the answer to 2 or 3 is yes, I'd be interested
in knowing how other people provide autodial for comm. boards.
Please send mail, if there is interest I will post a summary of responses
to the net.
Thanks.
--
Mark Roddy
Net working,
Just reading the news.
(harvard!talcott!panda!enmasse!mroddy)jack@boring.UUCP (06/28/85)
[Re: dialing by sending pulses to a certain pin on a modem] That's an old trick. What this in fact does is opening and closing the line fast (using DTR), since this is the same as the dial does. For anyone who is interested: I have a PDP-11 DL-11E driver that uses this trick to do dial-out on one of those pre-historic ASR-33 modems on machine 'htsa'. The driver is also intelligent about incoming and outgoing calls (which it can both handle). I haven't done any statistics, but the driver seems to get the correct number almost all the time (I never caught it dialing the wrong number, at 3 o'clock at night:-). If anyone is interested in the code (for V7 PDP-11, although it will probably port with adaptions for your device), I'll try to dig it cleanly out of the tty driver. -- Jack Jansen, jack@mcvax.UUCP The shell is my oyster.