ITEM: D1652L

Problem with flow control of a modem on serial port.

Question:

When running a RISC System/6000 model 320 on AIX 3.2.3e, the system
is having problems with flow control on the modem which is attached
to the serial port.  CRC errors are occurring every 4 KBytes.

Please provide how to setup a U.S. Robotics Sportster 14,400 modem.

Response:

As viewed with a breakout box, beyond any doubt, the U.S. Robotics 
Sportster causes CTS to go true at power-on when RTS/CTS hardware
flow control is configured.  The RISC AIX 3.2.+ doesn't like that.

After calling U.S. Robotics, they said that this is an assumption that
they made on the Sportster.  Even though it is a pure asynchronous
modem, they equate the &R0 feature (CTS tracks RTS), which is not used
in the standard fashion, to be a "synchronous" thing.  The Sportster
can not accept the &R0; it equates it to &R2.

The moral of the story is that a U.S. Robotics V.32 Sportster can not
be used on a RISC System/6000 which is running AIX 3.2.anything AND
using hardware flow control.

Note that this does NOT imply that a Sportster can not be used; it
states that it can not be used with hardware data flow control.



Support Line: Problem with flow control of a modem on serial port. ITEM: D1652L

Dated: September 1993 Category: N/A

This HTML file was generated 99/06/24~13:30:58

Comments or suggestions?
Contact us