30 Jul
2005
30 Jul
'05
12:11 a.m.
Just curious...has there ever been a device available to anyone's knowledge
that functions like an analog phone line and allows transmission via TCPIP?
For example, taking an older BBS system that has 5 internal modems in it,
and plugging the lines into this "mystery" device and then being able to
telnet to different ports and it makes the connection to one of the ports?
I've seen the UDS-10 device from Lantronix to emulate a serial modem, so
essentially you can telnet to it from another PC and it fakes the computer
into thinking someone's "ringing the phone, etc...but I want to take it one
step back...leave the modems in place but emulate the phone lines.
If it rings any bells, or if someone can think of a scenario this might be
needed in, please drop me a note and maybe it'll help me track down
something...
Thanks!
Pete
31 Jul
31 Jul
10:50 a.m.
Just curious...has there ever been a device available
to anyone's
knowledge that functions like an analog phone line and allows
transmission via TCPIP?
Yes and no. I've seen such devices in the form of cards that plug into
computers; with a little software, this adds up to what you describe.
They tend to have a fairly small market - generally people working on
telephony development of one sort or another - but they do exist.
(They tend to be somewhat expensive, in part because they're
complicated and in part because they're a low-volume item.)
You might also look at PBX systems; it may be easier to "forge" a T1 or
whatever into a PBX than individual POTS lines. (That is, I'm
suggesting a small PBX and a computer, with a (vary short) link between
them, so the PBX thinks the computer is its upstream CO.)
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1:17 p.m.
I have seen something like that. It essentially simulates a telephone
network. You would use it to test modems, for example, or to connect
machines that had internal modems. I think I saw it being sold by Black Box.
They are not the cheapest outfit in the world. It's like buying at the local
convenience store. IIRC they were over five hundred dollars.
HTH,
Gil
-----Original Message-----
From: cctech-bounces at classiccmp.org
[mailto:cctech-bounces at classiccmp.org] On Behalf Of Pete Bartusek
Sent: Saturday, July 30, 2005 2:11 AM
To: cctalk at classiccmp.org
Subject: Analog modem emulator?
Just curious...has there ever been a device available to
anyone's knowledge that functions like an analog phone line
and allows transmission via TCPIP?
For example, taking an older BBS system that has 5 internal
modems in it, and plugging the lines into this "mystery"
device and then being able to telnet to different ports and
it makes the connection to one of the ports?
I've seen the UDS-10 device from Lantronix to emulate a
serial modem, so essentially you can telnet to it from
another PC and it fakes the computer into thinking someone's
"ringing the phone, etc...but I want to take it one step
back...leave the modems in place but emulate the phone lines.
If it rings any bells, or if someone can think of a scenario
this might be needed in, please drop me a note and maybe
it'll help me track down something...
Thanks!
Pete
1 Aug
1 Aug
8:15 p.m.
On 7/31/05, Director <csmuseum at cse.uta.edu> wrote:
I have seen something like that. It essentially
simulates a telephone
network. You would use it to test modems, for example, or to connect
machines that had internal modems. I think I saw it being sold by Black Box.
They are not the cheapest outfit in the world. It's like buying at the local
convenience store. IIRC they were over five hundred dollars.
At Software Results, we used to make a two-port "CO Simulator" like
the one that Black Box sells. Ours was $700, and allowed you to make
simple connections, or to make "bad" connections on demand, depending
on what phone numbers you dialed. We used our own products to debug
autodialer software for our protocol engines.
Handy, but pricey.
-ethan
2 Aug
2 Aug
11:56 a.m.
I have seen something like that. It essentially simulates a telephone
network. You would use it to test modems, for example, or to connect
machines that had internal modems. I think I saw it being sold by Black Box.
They are not the cheapest outfit in the world. It's like buying at the local
convenience store. IIRC they were over five hundred dollars.
I am surprised, but I have never seen a published schematic for such a
unit, neither in a magaxine or on the web. They can't be _that_
complicated, surely?
-tony
1:23 p.m.
-----Original Message-----
From: cctech-bounces at classiccmp.org
[mailto:cctech-bounces at classiccmp.org] On Behalf Of Tony Duell
Sent: Tuesday, August 02, 2005 1:56 PM
To: cctalk at classiccmp.org
Subject: Re: Analog modem emulator?
...
I have seen something like that. It essentially simulates a
telephone
> network.
I am surprised, but I have never seen a published schematic
for such a unit, neither in a magaxine or on the web. They
can't be _that_ complicated, surely?
-tony
I think because there are several different options on things like ring
detection - current loop vs. wink start, IIRC. Plus you might want to check
out the various dialing options, etc. If you were in the business of making
(or maybe servicing) modems you wanted to be able to simulate all possible
situations. If you are only trying to make a connection between two boxes in
some specific situation you would be correct.
Gil
2:10 p.m.
On 8/2/05, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Having a) looked at competitors features, and b) built similar
products myself, the ones for sale are not simple. Ours used a pair
of SLICs (Subscriber Line ICs) just as a proper PBX or Telco switch
port would use. In between a few sq in. of through-hole passives, we
had an 8048-type microcontroller generating dial tones, interpreting
telephone numbers, triggering ring voltages, etc. Ours, being two
lines, fit in a standard Pac-Tec box that was about 6" x 6" x 2" and
was *covered* in parts. SMT could have made it cheaper, but it was
designed in a non-modern environment for low-volume production. We
didn't make enough to fill a shopping cart.
-ethan
...essentially simulates a telephone
network.... sold by Black Box.
I am surprised, but I have never seen a published schematic for such a
unit, neither in a magaxine or on the web. They can't be _that_
complicated, surely?
2:42 p.m.
On 8/2/05, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Having a) looked at competitors features, and b) built similar
products myself, the ones for sale are not simple. Ours used a pair
of SLICs (Subscriber Line ICs) just as a proper PBX or Telco switch
You and I have different ideas of 'simple'. A copuple of SLICs and a
microcontroller is not complicated, at least not compared to many other
projects that I've built, and that I've seen in the magazines, over the
years.
One UK magazine published a design for a telephone exchange. It handled
16 lines, expandable to 32. It was a load of CMOS logic, crosspoint
switch ICs, analogue stuff, etc. No microcontrollers (I think there was
an EPROM to handle the mapping from the telephone number to the
switches), no special SLICs It alloweed several simultaneous connections,
produced dial tone, engagued tone, etc
Surely a 2 line box that produces the right tones and the ringing voltage
would be a lot simpler than that.
-tony
...essentially simulates a telephone
network.... sold by Black Box.
I am surprised, but I have never seen a published schematic for such a
unit, neither in a magaxine or on the web. They can't be _that_
complicated, surely? 
31 Jul
31 Jul
2:34 p.m.
"Pete Bartusek" wrote:
Just curious...has there ever been a device available
to anyone's knowledge
that functions like an analog phone line and allows transmission via TCPIP?
For example, taking an older BBS system that has 5 internal modems in it,
and plugging the lines into this "mystery" device and then being able to
telnet to different ports and it makes the connection to one of the ports?
Heh. I worked one on once, but it had 2000 modems :-) it was used by
large ISP to field dial-in calls but it could do dial-out also.
You might want a line emulator, which is sort of a "ring down line in a box".
It has 2 rj-11's and when one side goes off hook it can generate ring
voltage on the other side. Those boxes are not very expensive.
-brad
3:11 p.m.
On Sat, 30 Jul 2005, Pete Bartusek wrote:
Just curious...has there ever been a device available
to anyone's knowledge
that functions like an analog phone line and allows transmission via TCPIP?
For example, taking an older BBS system that has 5 internal modems in it,
and plugging the lines into this "mystery" device and then being able to
telnet to different ports and it makes the connection to one of the ports?
I've seen the UDS-10 device from Lantronix to emulate a serial modem, so
essentially you can telnet to it from another PC and it fakes the computer
into thinking someone's "ringing the phone, etc...but I want to take it one
step back...leave the modems in place but emulate the phone lines.
If I understand what you're asking for, you would need something that
generates a ring signal, then converts TCP/IP packets to a modem carrier
and vice versa. Pretty funky. Hmm, check out Cisco's offerings.
If it rings any bells
So to speak.
--
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4:08 p.m.
At 08:11 30/07/2005, Pete Bartusek wrote:
Just curious...has there ever been a device available
to anyone's knowledge
that functions like an analog phone line and allows transmission via TCPIP?
For example, taking an older BBS system that has 5 internal modems in it,
and plugging the lines into this "mystery" device and then being able to
telnet to different ports and it makes the connection to one of the ports?
It might be you just need a terminal server with dial-out capability and
modems, or one with built in modems.
Then to link it to your BBS, you need a line emulator.. I've had success
with just hooking modems back to back, at times, sometimes with a 9V
battery to assist with line current detection (there are circuits about to
show how to wire this properly!) but if your answering modems are picky on
the ring signal (and can't detect e.g. a pulse-dial as a ring) then you
need something a bit more clever to make the ring signal.
It's often easier, and I've done this when testing things in the past, to
pick up an old, small, PABX second hand dirt cheap, which you can use
stand-alone, dialing extension->extension.
Rob
6852
days inactive
6855
days old
10 comments
8 participants
participants (8)
-
ard＠p850ug1.demon.co.uk -
brad＠heeltoe.com -
classiccmp.org＠irrelevant.fsnet.co.uk -
csmuseum＠cse.uta.edu -
ethan.dicks＠gmail.com -
mouse＠Rodents.Montreal.QC.CA -
pete＠bartusek.com -
vcf＠siconic.com