Using internal modems

Thread View: comp.sys.ibm.pc.rt

1 messages

[T] Back to Threads [V] Tree View [G] Group Articles

1 total messages Started by Jamie Watson Wed, 04 May 1988 18:18

#1383

Author: Jamie Watson
Date: Wed, 04 May 1988 18:18

22 lines
1424 bytes


Some time ago I posted a question here about using a PC internal modem in
an RT with AIX.  The problem was that the first character from each string
sent to the modem was lost.

Through the efforts of the IBM software support person in Zuerich, I found
that the problem was that the UART used in most modem cards, the NS8250, is
too slow for the AIX serial device driver.  There is a faster version of
that UART, the NS16450, which is pin compatible with the 8250.  Some of the
modem manufacturers are using the newer chip in their modems now - Hayes, I
know for sure, and probably others.  However, the new modems are not yet
available in Europe, and it may be some time (if ever) before the various
PTTs approve them.  

There is hope, though.  Because the 16450 is pin compatible with the 8250,
those who have (or can get) a modem with the older chip can simply buy a
new chip from the local National Semiconductor distributor, and change it
themselves.  I've done it on a MultiTech PC3 (it's being used to send out
this message), and the IBM person has done it on a genuine Hayes.

jw

Thread Navigation

This is a paginated view of messages in the thread with full content displayed inline.

Messages are displayed in chronological order, with the original post highlighted in green.

Use pagination controls to navigate through all messages in large threads.

Back to All Threads