From: Frank Lowe (
Date: Mon Sep 14 1992 - 19:13:59 CDT

Many thanks to:

Christian Lawrence <> (Ron Stanonik)
Mike Raffety <>
Philip.Helsel <


I have been unsuccessfully trying to configure Telebit QBlazer modems
to work on a Sun 4/670 - SunOS 4.1.2. The modems are connected to ports
ttyh9 and ttyha of a 16 port ALM-2 board. Two 2400 baud Everex
modems have been working on these ports for some time.


ALM-2 ports 4-15 are not configured for modem control. This
apparently does not bother the 2400 baud Everex modems, but
prevents the faster QBlazers from functioning. Pin-outs for
the ALM-2 are shown below.

Two solutions appear possible.

        1. Configure the modems on ports 0-3.
        2. Disable hardware flow control on the QBlazer (S58=0)

I have tried solution 2 and it works. Relevant QBlazer settings
are shown below. I plan to try solution 1 this week and expect that it
also will work. The rest of the setup (building cu devices, ttytab, etc)
is just as described in the Sun System and Network Administration Manual.



Frank Lowe
Southwest Foundation For Biomedical Research
San Antonio, Texas

internet: (
voice: (512) 674-1410
fax: (512) 670-3316


ALM-2 Information:

                    ALM-2 RS232 Port 0-3
                   (25-Pin D-Sub, Female)

                Pin Signal Pin Signal
                2 TxD 8 DCD
                3 RxD 15 TxC
                4 RTS 17 RxC
                5 CTS 20 DTR
                6 DSR 24 TxCO
                7 GND

                   ALM-2 RS232 Port 4-15
                   (25-Pin D-Sub, Female)

                Pin Signal Pin Signal
                2 TxD 8 DCD
                3 RxD 20 DTR
                7 Gnd


QBlazer - Version MA1.01
Relevant or non default settings:

E0 no echo
Q0/V0 send numeric results codes
X0 minimum result code set
&C1 assert DCD only when remote carrier signal is present
&D3 hangup and reset profile A if DTR loss
&R2 hardware flow control honored if enabled
S0=1 auto-answer after 1 ring
S50=0 auto speed determination modem<->modem
S51=4 DTE interface speed 9600
S58=0 hardware (RTS/CTS) DTE flow control
S60=0 8 data bits, no parity, 1 stop bit data format (p8 set in gettytab)
S68=2 hardware (RTS/CTS) DCE flow control

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