Very Computer

Modem manufacturers drive me nuts.

A customer has a US Robotics Sportster 14.4 modem that he
wants to use for dial in.  The manual is incomprehensible
to him, and doesn't seem to have any reference to DTE
rate or anything like it.

So, he called USR for help, and of course was told that
he doesn't need to set the DTE rate.  Well, of course
he *does*, 'cause this is Unix.  USR's response?  "We
don't support Unix".

As he had the benefit of some coaching from me before making
the call, he said that he wasn't asking them to support
Unix or to know anything about it, and that the ONLY thing
he needed to know was how to fix the DTE rate at 19.2.
No luck.  He "doesn't need to do this", and they don't
support Unix.  End of conversation.

I know the modem supports this.  If anyone can tell me the
at commands to set this puppy at 9600, 19.2, 38.4, I
would sure be a lot happier :-)  I'm pretty sure that
anything else I need is in their manual, but if you
happen to know something that isn't either obvious or
standard Hayes...

--
Tony

<snipped portion referring to USR 14.4 modem and USR's poor support>

: I know the modem supports this.  If anyone can tell me the
: at commands to set this puppy at 9600, 19.2, 38.4, I
: would sure be a lot happier :-)  I'm pretty sure that

<snipped ending>

You need to make changes to the following files:

/usr/lib/uucp/Devices
/usr/lib/uucp/default/atdialUSR  <=== assuming OSR5
/etc/default/atdialUSR  <== assuming SCO 3.2v4.x
/etc/inittab

In /usr/lib/uucp/Devices (I'll use tty2A here since you didn't specify):

ACU tty2A - 9600-38400 /usr/lib/uucp/atdialUSR
Direct tty2a - 38400 direct

In ../default/atdialUSR:

Change the RTC_9600=CONNECT to RTC_9600=not used
Change the RTC_38400=not used to RTC_38400=CONNECT

In /etc/inittab:

Change Se2A:234:off:/etc/getty -t60 tty2A m
To     Se2A:234:off:/etc/getty -t60 tty2A o

Issue the following commands:

disable tty2a
enable tty2A
chown uucp /dev/tty2A
chown uucp /dev/tty2a
chgrp uucp /dev/tty2A
chgrp uucp /dev/tty2a

The modem lights should now display AA TR CS

Dial in connections need to have their serial-to-modem rate set to 38400.
Remember, the serial-to-modem rate is different from the advertised speed
of the modem .. that speed is the maximum connect rate .. two different
things!!!

If 38400 gives you trouble .... try 19200 instead .. the /etc/inittab
entry would have an "n" instead of an "o".  Applicable changes to the
other files would be needed as well.

With this config, any speed modem from 9600 on up should be able to
connect and get a login.
--

###################################################
              I brew, therefore I am.

: Dial in connections need to have their serial-to-modem rate set to 38400.
: Remember, the serial-to-modem rate is different from the advertised speed
: of the modem .. that speed is the maximum connect rate .. two different
: things!!!

Um, Steve?  Thanks, but..

If you had read more carefully, you might have noticed that I didn't
ask for any help configuring Unix.

I need to know the AT commands to set the serial to modem rate (DTE)
rate to 38.4, 19.2 and 9600 on this USR modem.  I need all of these
because I don't know what his serial ports can handle, so I have
to experiment.

--
Tony

You might want to try the USR144 dialer, it takes care of this.
But if you need to do it manually, the DTE rate can be locked in
by sending an AT command at the speed you want, and then sending
an AT&B1 , which locks the baud rate to the last at command. So if
you configure the port at 19200, send AT<cr> AT&B1<cr>, the DTE will
be locked at 19200, regardless of what speed the modems negotiate.

Danny Aldham

: : Dial in connections need to have their serial-to-modem rate set to 38400.
: : Remember, the serial-to-modem rate is different from the advertised speed
: : of the modem .. that speed is the maximum connect rate .. two different
: : things!!!

: Um, Steve?  Thanks, but..

: If you had read more carefully, you might have noticed that I didn't
: ask for any help configuring Unix.

: I need to know the AT commands to set the serial to modem rate (DTE)
: rate to 38.4, 19.2 and 9600 on this USR modem.  I need all of these
: because I don't know what his serial ports can handle, so I have
: to experiment.

Um, OK.

I guess you oughta RTFM then. :)

The USR Sportster will allow you to fix the serial rate so it will not
vary with connect speed.  

--

###################################################
              I brew, therefore I am.

Quote:>You might want to try the USR144 dialer, it takes care of this.
>But if you need to do it manually, the DTE rate can be locked in
>by sending an AT command at the speed you want, and then sending
>an AT&B1 , which locks the baud rate to the last at command. So if
>you configure the port at 19200, send AT<cr> AT&B1<cr>, the DTE will
>be locked at 19200, regardless of what speed the modems negotiate.

There are basically 3 ways to establish a connection:

1. Using ATD

2. Using ATA

3. Using auto-answer (i.e. when S0 is not 0).

Some modems may provide other means (such as dial on DTR being raised) but
that's not really important.

When &B0 is set the modem switches to a DTE speed dependent on the connection
rate - that is easy.

When &B1 is set the DTE speed is set to a predetermined value:

a) with ATD or ATA it remains at the speed at which the ATD or ATA commands
   were sent.

b) If the modem auto-answered it switches to the speed stored in
   NVRAM (which you can inspect using ATI5, or possibly ATY5 on Sportsters).

   The speed stored in NVRAM is set when you issue an &W command - it is
   set to the current DTE speed. So the sequence of operations you need to
   set this is:

Start your comms program setting speed and word format (8 bits no parity
should always work). Then issue:

ATZ
AT&B1&W      Make sure everything else such as flow control is set up here.

and to check:

ATI5

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: When &B0 is set the modem switches to a DTE speed dependent on the connection
: rate - that is easy.

: When &B1 is set the DTE speed is set to a predetermined value:

This is moronic.  No, Lawrence, not you or your post, but this
incredibly lame method of fixing the DTE rate.

Give me a Multitech anyday.  AT$SB38400.  No wondering, no
worry, no b.s.

I am absolutely stunned.  I guarantee I will *never* recommend
USR modems to anyone.  Heck, they deserve that for their "We
don't support Unix" stupidity, but if *this* is how you have
to set DTE... well, "wow" is all I can say.

--
Tony

Quote:>Give me a Multitech anyday.  AT$SB38400.  No wondering, no
>worry, no b.s.

Quote:>I am absolutely stunned.  I guarantee I will *never* recommend
>USR modems to anyone.  Heck, they deserve that for their "We
>don't support Unix" stupidity, but if *this* is how you have
>to set DTE... well, "wow" is all I can say.

--
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