2 Aug
2005
2 Aug
'05
11:41 a.m.
Sellam:
You're description is based on a remote telnet inbound connection
where you're coming in over the internet and using the host PC and the PBX
to route the call to the right one of the four modems on the computer from
the original example. In this case I agree with you -- it's one inbound
connection reaching one destination.
I was talking about the VCF exhibit, where I believe you would still
need a modem bank. If I have two Apple II's each with a modem plugged into
the PBX and I "dial" extension 101 which is the host PC, won't I get a busy
when the second Apple dials "101"? I think you do need a modem bank on the
host PC with the fallover feature on the PBX programmed properly. The PBX is
simply acting as the "phone company" for purposes of connecting the two.
Rich
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
On Behalf Of Vintage Computer Festival
Sent: Tuesday, August 02, 2005 2:22 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: RE: Analog modem emulator?
On Tue, 2 Aug 2005, Cini, Richard wrote:
Refining the BBS idea a bit, the problem with it is
multiplexing. You'd
need
to run a modem bank (like Hayes or Multitech) into the
PBX and use an
n-port
serial card in the host PC. The PBX I'm sure can
be set for number
fallover
so if you keep dialing extension "101" and
it's busy, it will roll to
extension 102, etc.
The modem bank off the host is not necessary. The PBX solves the
multiplexing problem. You have one modem on the gateway PC that is
connected to an extension on the PBX. It can then dial any one of the
other extensions which will then connect it to one of the modems on the
target PC.
I used to have a 24-modem (2400 baud) Multitech modem
bank from an old DEC
installation but I got rid of it a long time ago. Just another piece of
hardware I should have kept...
That stuff is really common if you know where to look ;)
--
Sellam Ismail Vintage Computer
Festival
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2 Aug
2 Aug
12:05 p.m.
On 8/2/05, Cini, Richard <Richard.Cini at wachovia.com> wrote:
I was talking about the VCF exhibit, where I
believe you would still
need a modem bank. If I have two Apple II's each with a modem plugged into
the PBX and I "dial" extension 101 which is the host PC, won't I get a
busy
when the second Apple dials "101"? I think you do need a modem bank on the
host PC with the fallover feature on the PBX programmed properly. The PBX is
simply acting as the "phone company" for purposes of connecting the two.
The "CO emulator" sold by Black Box will do this, for limited numbers
of connections. The model I have is smaller than a phone book and
supports 4 phones. The lingering question I have (since I haven't
powered it up in 10+ years) is if it supports two simulaneous
connections, or only allows one of three extensions to call the
primary. In any case, for at least a single connection, it allows two
modems to talk, each thinking they are attached to the POTS network -
dial tone, ring tones, ring voltage, the whole enchilada.
Of course, if you want to support more than one or two lines, a small
PBX is the way to go.
My old COMBOX product would only be useful for point-to-point. It's
as real a connection as a PBX, but only two lines. In practice, that
should be enough, unless you really want to sit people down in front
of a machine and have them pretend they are a BBS user and make them
choose from two or three different destinations. Entertaining, but
time consuming.
Of course, you'll have to simulate busy signals as well ;-) [ except
when Star Trek is on TV - that was always the best time to call the
local BBSes - all the nerds were in front of their televisions, and
they didn't have their computers in the same room back then ]
-ethan
1:15 p.m.
On Tue, 2 Aug 2005, Cini, Richard wrote:
I was talking about the VCF exhibit, where I believe
you would still
D'oh! Sorry.
need a modem bank. If I have two Apple II's each
with a modem plugged into
the PBX and I "dial" extension 101 which is the host PC, won't I get a
busy
when the second Apple dials "101"? I think you do need a modem bank on the
host PC with the fallover feature on the PBX programmed properly. The PBX is
simply acting as the "phone company" for purposes of connecting the two.
In telco parlance this is what's called a "hunt group", where you have
multiple destinations in a group that all have the same function where it
doesn't matter which one you reach (for instance a customer support line).
So you have one number assigned to the entire group, and the PBX will pick
the first available extension based on some simple algorithm (hunt from
top down, bottom up, least used, etc.)
In the VCF exhibit, my thinking is that each exhibitor is assigned an
extension, and so people on the outside (or inside) can call into a main
number and then from there transfer themselves to a particular exhibitor's
extension. If there's a TCP/IP to telco gateway (what we are discussing
here) then the gateway PC would have a bank of modems connected into the
PBX and anyone coming in on a TCP/IP "call" would be randomly assigned a
physical modem, and from there they could dial into any available
extension. If the extension is busy, they try another (or get routed to
e-mail to leave a message ;)
--
Sellam Ismail Vintage Computer Festival
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2 comments
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ethan.dicks＠gmail.com -
Richard.Cini＠wachovia.com -
vcf＠siconic.com