SUMMARY: serial boards

From: Michael H. Morse (
Date: Mon Nov 09 1992 - 20:42:27 CST

My original request asked for recommendations for serial boards for
Sun systems.

>Can anybody recommend a vendor for a serial board? I want to hang
>4 to 8 v.32 modems off a Sparc2. Any issues I should watch out for?

I recieved many recommendations, so I'd say that there are a lot of
good vendors out there. Nobody sent any tips on ones to stay away
from. Several people suggested that I use a terminal server, because
"serial boards" are a headache. I've got a terminal server (and a
headache), which is why I am looking at serial boards!

My suspicion is that supporting a virtually infinite user community
with an endless diversity of modems, terminals, and skills is
inherently a headache, and my search for the cure will be fruitless.
So, first I'm going to try to find why my terminal server (3Com)
refuses to wake up when a modem connects to it, and pending the
resolution of that, look into either a new terminal server or one of
the boards recommended below.

One reason I wanted to get rid of the terminal server is that I find it
difficult to use it for Xmodem, and other file transfer protocols that
require an 8-bit data path. From the discussion resulting from my
question (and personal experience), I get the idea that doing Xmodem
over 9600 baud modems is problematic anyway. The reason is that you
can't use x-on/x-off flow control, so you must use hardware flow
control, which is a bit unusual, and besides, I don't have much
control how my users configure their modems.

Thanks to everyone that replied. For the most part, I've included the
full text of the replies, limiting my editing to deleting mail
headers, signatures and white space.


From: Jim Davis <>
We've used Danford SPPE-6500 4-port boards for terminals with good
results. I haven't tried V.32 modems myself, but a neighboring site
has used them for that, and I haven't heard any complaints.

Try CoSystems. They give you 12 ports (if I remember correctly) for
half the price of the board from Sun (which only gives you 2 ports, too).

Make sure all the serial ports on the card permit full modem control.
Some boards only allow some ports and not all to have full modem

Try "Central Data" (217)359-8010, their scsi based products look
promising but we have not bought any ourselves yet.

Try "Chase Research" (615)872-0700, their network based products look
promising but we have not bought any ourselves yet.

I have a personal preferance for network based products since we have
suns, macs, & dos machines all connected via ethernet because they do
not require a host machine.

From: Russ Poffenberger <>
We use the Central Data SCSI terminal server, up to 16 full modem
control serial ports, and all you do is connect it to the SCSI port. No
opening the case.

From: Gary Blumenstein <>
I think you'll find the ones made by Aurora one of the best.

From: Peter Shipley <>
I have used Central data serial board (they connect to the SCSI bus
thus you can use it on other hardware in the future). I had eight
tb2500 doing uucp at rates of 9600 -> 19200 with out problems. once
installed they work just like the regular serial that are attached to
the CPU (you need to install a new device driver, but that si trival).
They give full modem contral and their service is very good (when they
first came out a year or so ago there was a bug is the driver that
caused the port to lock up, when I reported the problem they looked
into it and came up with a patch *that day* and I had the fix installed
before the end of the day!

From: Matt Goheen <>
I don't have any recommendations for a particular board, but you should
make sure it does RTS/CTS (both directions, i.e. both RTS and CTS) and
that it handles 38400 baud (a v.32bis modem using v.42bis can easily
exceed a 19200 baud serial line rate). Other than that, I guess I'd
like to know what you find...

From: Christopher Nims <>
If I were you, I'd skip that idea and purchase a small terminal server. We
had nothing but problems with modems hanging directly off the sun. Not to
mention the fact that suns can't talk to modems reliably over 19200 bps.
We decided to go with a Cisco CS-500 terminal server.

From: Ed Romascan <mrt!>
These are the best AND cheapest.

Contact: B. Michael Seidel
Phone 800-285-8990
Fax 619-457-0798

[Ed enclosed a fairly large product description. Write me if
 you'd like a copy.]

From: Jae Chung <eclipse!>
        Yes, there are things that you should watch out for....

        First, all of the ports you buy support modem decipline or not...
        for instance ALM-2 board from SUN only supports first 4 ports out
        of 16 ports to fully support modems.

        I'm the manager of Systems Engineering Department, and our product
        (DEI-1 or DEI-2) support modem line on every single ports we
        provide up to 38.4K baud rate.

        If you need have an info on our product, contact our sales staff
        at 818) 577- 4252

From: Larry Chin <>
How about SUN themselves ? They make a SPIF ( Serial parallel Interface ). As
the name implies there are serial ports ( 8 ) and parallel ports ( 1 ). I don't
know how much they are but I have found them to be very reliable and easy
to install.

From: Jim Lick <>
Make sure whatever you buy does BI-DIRECTIONAL rts/cts (hardware) flow
control. The Sun ports only do one directional rts/cts flow control.
Flow control is ESSENTIAL for high speed modems, and xon/xoff flow control
interferes with anything expecting a clean 8-bit channel such as SLIP,
file transfer protocols like xmodem, ymodem, zmodem (but kermit can handle
just about anything), and some key-sequences in emacs, among other things.

From: Kevin Sheehan {Consulting Poster Child} <ups!>
I can recommend the DEI boards from GNP - they've always worked for me.

Uninet sells scsi based serial/parallel expansion boxes. High
performance, non-standard baud rates, you don't use of need an Sbus
slot, no new drivers added, and portable to other machines if you
switch later. If you know Chris Meyers, you might ask him for a
reference, I believe he's still using one on wuarchive.

From: Randy Davis <megatek!>
  I've been VERY happy with the installation AND performance of the CoSystems
"CoAlm" board. They are cheaper and more-powerful serial boards than Sun's
ALM board. We've been running a number of 9600 baud modems and a 38400 baud
modem full tilt off one for almost a year now.

  I am using a sixteen-port CoAlm, made by CoSystems, to handle all of my
modem traffic including external email, a full newsfeed, and an InterNet SLIP
connection. Presently five Trailblazers (two T1000's, two TB+`s, and
the T3000 WorldBlazer for SLIP). All the serial ports to the modems are
running 9600 baud, except the WorldBlazer which is run at 38400 baud. News
transfers are running full blast (via the 38.4k SLIP connection) for more than
a couple of hours per day, as well as a lot of uucp traffic on the other
modems, and the board has exhibited no problem in the ten months its been
in service. I beleive it can run at least 19,200 baud on ALL ports
simultaneously with full usage on all ports and not be bothered, unlike
other serial boards.

  The thing installed without a hitch of any kind on a Sun3/260 running
SunOS 4.1.1, and I beleive it was cheaper than Sun's board...

  I beleive that CoSystems can be reached at:

           CoSystems, Inc.
           2250 Scott Blvd, Bldg. 61-01
           Santa Clara, CA 95054
           Tel: (408)748-2190
           Fax: (408)988-0785

  Just a satisfied customer...

Michael Morse                           Internet:
National Science Foundation               BITNET: mmorse@NSF
1800 G St. N.W. Room 401               Telephone: (202) 357-7659
Washington, D.C.  20550                      FAX: (202) 357-7663

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