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Re: ISDN Support



Dave Cinege writes:
 > On 21 Apr 1997 03:58:51 -0000, Richard Sharman wrote:
 > >Dave Cinege writes:
...
 > > > Ahhhhaaa! And you are using this with linux? Are you sure it is opening the 
 > > > 16650 at 230K?

 > >Well, I *think* so.  How can I tell?  I use setserial with spd_cust
 > >and a divisor of 1 with the card jumpered to a base of 3.6864 Mhz;
 > >this is supposed to produce 230.4K.  Before doing that, using spd_vhi
 > >giving 115000 bps I tell the Bitsurf the speed is now 230400.  I then
 > >switch speeds and the bitsrfr responds.  It no longer talks to me if I
 > >talk to it at 115000.  In fact, it often resets when I do.
 > 
 > Hmmm, this doesn't sound right. Sorry but this is getting beyond my 
 > knowledge. I've never even used spd options....my file looks like this:
 > 
 > STD_FLAGS="session_lockout ^fourport"
 > SETSERIAL=/bin/setserial
 > 
 > echo -n "Configuring serial ports...."
 > 
 > ${SETSERIAL} -b  /dev/ttyS0 uart 16550A port 0x3F8 irq 4 ${STD_FLAGS}
 > ${SETSERIAL} -b  /dev/ttyS1 uart 16550A port 0x2F8 irq 3 ${STD_FLAGS}
 > 
 > ${SETSERIAL} -bg /dev/ttyS*
 > 
 > In ppp.options_out I just set a rate of 115200 and everything seems to work 
 > fine with my modem. I assumed all you would have to do is change the rate in
 > this file to 230400.
 > 
 > Anybody know whats going on here? 
 > 
 > I'm certainly interested because I intend to be getting a byte runner 16650 
 > card and ISDN TA in a about a week.
 > 

I didn't think that the speed parameter actually did anything in pppd.
A quick look at the code shows that it seems to actually set the speed.
I tried changing it to 230000.  It didn't produce any error (nor log),
but the ip-up script was now called with $3 (the speed) of 0, prevoiusly
it was 38400.  Actually, it's not that simple.  I'm using diald, so
the speed is specified as a diald option not a pppd option.

The documentation from Byte Runner is a bit skimpy on details (but at
least they did have a Linux directory on their disk,  containing a
recent version of setserial).

This is what I found from experimenting,  in case it helps.  If anyone
knows anything different, plesae let me know.  Assuming you have the
card jumped to the middle base frequency (3.6874 MHz), then:

- if you DON'T set the baud_base parameter on setserial
  - setting the speed with stty of N gives you 2*N,  e.g. an
    stty 9600 < /dev/ttyS2 gives a speed of 19200.

- if you DO set baud_base to 230400 with setsetserial, then
   what you set with stty is what you get.

So one method of getting the card to be 230400 is to leave baud_base
at its default of 115200,  do a setserail spd_vhi and use 38400 as the
speed.

However,  if you want any other speed you have to remember to half the
value!

Alternatively,  if you set baud_base to 230400 then speed up to 38400
are ok as is,  spd_vhi give you 115200.   To get 230400,  you have to
(I think!) use spd_cust and set the divisor to 1.

It seemed to me that if you want to go lower and use something other
than spd_cust you must also set divisor to 0.  It seems that if the
divisor is non zero this overrides everything else.

Richard


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