From: peterson@ZGNews.LoneStar.Org (Bob Peterson)
Newsgroups: comp.dcom.modems
Subject: Re: Speaking of terminal servers...
Date: Fri, 25 Sep 92 09:55:35 CDT
Distribution: world
Organization: The Zeitgeist BBS, Plano, TX  214 596 3720

tom@ssd.csd.harris.com (Tom Horsley) writes:

> I suspect a configuration like this may be what I wind up with some day, but
> I am operating from a state of absolute ignorance about how terminal servers
> work. I have lots of questions someone may be able to answer (it is always
> more fun to ask the net than to do something obvious like talk to the
> manufacturer :-).
> 
>    * What does a terminal server look like to the host machine (in this case
>      it will be a U**x workstation)? Does it just look like someone
>      initiated a telnet session into the workstation?

  Yes.  From our Annex we telnet or rlogin to the remote machine across
the Ethernet LAN.

>    * How does the workstation use a modem connected to a terminal server
>      to dial out? Do I initiatiate some sort of telnet session to the server?

  Correct, I believe.  We don't actually do this, but I have been known
to telnet to the Annex from my workstation.  I don't have enough
authority to actually connect and dial out, but I've seen it done once
or twice by the administrator.

>    * If the server is just running telnet sessions, how do I do things
>      like transmit or recieve binary files which might trigger the telnet
>      escape character?

  The Annex we use can be set up for a fully transparent link, i.e., I
can run XModem, YModem, ZModem, uucp g, etc., across the link.  This
does require setting some parameters, some of which weren't obvious.

>    * Do terminal servers support the RTS/CTS flow control which most high
>      speed modems use? Can I just connect the modem and server at 58K baud
>      and let the flow control deal with varying connection speeds?

  The Annex 3 terminal server does support enough wires, and has the
appropriate software, to do hardware flow control.  Our Annex 2 does
not support hardware flow control for modems, at least partly due to
lack of wires (signals) in the serial ports.

>    * Is there anything about a terminal server which would prevent me from
>      being able to use the Fax and voicemail features of the spiffy new
>      modems being made today? (Obviously I need software to support it on
>      the host machine, but would the terminal server also need special
>      software?).

  I'd be very careful about such capabilities.  Remember, the terminal
server answers the phone, not the host machine.  This probably means
you'd have to dedicate a modem to inbound fax calls.  I don't know what
this implies for voicemail.  You really should talk to the terminal
server vendors about this one.

>    * Who makes nice reliable and reasonably priced terminal servers (I would
>      only need something like 4 to 8 ports, nothing big).

  I believe Annex makes small models.  At this level you might also want
to consider some sort of multiport addon for your host, e.g., a port
expansion connected to the SCSI bus.

> domain: tahorsley@csd.harris.com       USMail: Tom Horsley

  Our environment actually consists of a Microcom bank of rack mount
modems plus two Annex terminal servers.  The Microcom modem controller
does things like require a login id and password before allowing the
caller to talk to the Annex, as well as implementing a callback
facility.  The callback facility accepts a login, then calls the user
back at either a pre-defined number or a number specified by the user
after verification of the password.  All inbound calls are logged.  This
setup works quite well, and provides better security than simply
connecting the modems directly to the host machines.

  The logging also provides a history for each modem, which helps
isolate phone line, modem, and port problems.

  All the above happens at work.  I'm posting this from home.  I have
no connection with any company mentioned above, except as a customer or
user.

    Bob


Bob Peterson          Waffle BBS: peterson@ZGNews.LoneStar.Org
P.O. Box 865132       Internet: peterson@csc.ti.com  TelCo: 214 995-6080 days
Plano, Tx 75086-5132  BBS: 214 596-3720 @1200, 2400, 9600-14400 (HST & V.32bis)