5 Nov
2015
5 Nov
'15
10:59 a.m.
I've been trying for the past week to verify that telephony on my teletype
machine (model 33) is functioning properly but the biggest hurdle I am
running into is I have nothing to easily dial into. Everyone I know off hand
either don't have a modem anymore or theirs is a Winmodem which won't work.
There's only one phone line into the residence here and those bluetooth to
cellular POTS bridges are too lossy to make do and connect to a machine
here. There is that youtube video of the model 37 apparently connecting to a
system at the Living Computer Museum in 2013 (MikoF6KZjm0) where they dialed
into a BBS I've never seen listed anywhere but the number listed no longer
seems to work and in the description it states the service is no longer
available. What other public systems are still out there that will work this
speed or possibly better yet, is there anyone out there willing to try a
teletype-to-teletype conversation?
-John
5 Nov
5 Nov
11:17 a.m.
On Thu, 5 Nov 2015, John Ball wrote:
I've been trying for the past week to verify that
telephony on my teletype
machine (model 33) is functioning properly but the biggest hurdle I am
running into is I have nothing to easily dial into. Everyone I know off hand
either don't have a modem anymore or theirs is a Winmodem which won't work.
There's only one phone line into the residence here and those bluetooth to
cellular POTS bridges are too lossy to make do and connect to a machine
here. There is that youtube video of the model 37 apparently connecting to a
system at the Living Computer Museum in 2013 (MikoF6KZjm0) where they dialed
into a BBS I've never seen listed anywhere but the number listed no longer
seems to work and in the description it states the service is no longer
available. What other public systems are still out there that will work this
speed or possibly better yet, is there anyone out there willing to try a
teletype-to-teletype conversation?
Is yours ASCII or "Baudot"? (there are some issues of the correct name for
that)
Some non-computer organizations still have TTY/TDD service for deaf users.
That traditionally was "Baudot" at low speed, and some still work. Some
are still posted/advertised, but not all are working. There are still
some "relay" services available that are a live operator with a voice line
and a TTY.
12:14 p.m.
> I've been trying for the past week to verify
that telephony on my teletype
> machine (model 33) is functioning properly but the biggest hurdle I am
[...]
Is yours ASCII or "Baudot"? (there are some
issues of the correct name for
that)
If it's a model 33 it has to be ASCII. The 'Baudot' one is the Model 32 IIRC.
[Yes OK, there were plenty of other 'Baudot' machines made by
Teletype, but the Model 32 is similar to the Model 33]
IIRC 'Baudot' should really be called ITA2. ITA5 is ASCII. (ITA = International
Telegraph Alphabet). Is ITA1 Morse? What were/are ITA3 and ITA4?
The original Baudot code, as used on the 5-key chording keyboard thing
was also a 5 level code, but quite different in how the characters were encoded. There
was also Murray code which is similar to ITA2 but one major difference is that
there are 'letter space' and 'figure space' codes (which move the carriage
one character
and select the appropriate 'shift' rather than letters and figures shift
characters which
just select the shift, along with a seprate space character. So in Murray code you could
not send ABC12XY63, it would have to be ABC 12 XY 63
-tony
12:48 p.m.
The Baudot thing sure brings back some memories. I still recall hooking
teletype's up thru KW-7 boxes, and performing ryryryryryryryryr test.
I don't recall enough of the specifics, but it was either
Y = 10101
R = 01010
or reversed.
https://en.wikipedia.org/wiki/Baudot_code
Jerry
On 11/ 5/15 02:14 PM, tony duell wrote:
The original Baudot code, as used on the 5-key chording keyboard thing
was also a 5 level code, but quite different in how the characters were encoded. There
was also Murray code which is similar to ITA2 but one major difference is that
there are 'letter space' and 'figure space' codes (which move the
carriage one character
and select the appropriate 'shift' rather than letters and figures shift
characters which
just select the shift, along with a seprate space character. So in Murray code you could
not send ABC12XY63, it would have to be ABC 12 XY 63
-tony
1:18 p.m.
The Baudot thing sure brings back some memories. I
still recall hooking
teletype's up thru KW-7 boxes, and performing ryryryryryryryryr test.
I don't recall enough of the specifics, but it was either
Y = 10101
R = 01010
or reversed.
Ah yes... One of the classic tests for problems in the receiver and comms link, but
not the only one. A system with poor low frequency response (for example) might
handle alternating mark and space correctly but fall down on things like 11110
I have a test message generator that can sent that, various alternating signals (without
start and stop bits), user-entered characters (on a row of switches) and so on. And
distort them by lengthening and shortening pulses to check how well the receiving
device copes with mangled signals. I also have the distortion measuring set, a special
oscilloscope to check for distorted signals, test relays for contact bounce, bias and
transit time, etc.
I really must get my Creed 7E and 444 running again...
-tony
2:49 p.m.
On Thu, 5 Nov 2015, tony duell wrote:
Telegraph Alphabet). Is ITA1 Morse? What were/are ITA3
and ITA4?
Which Morse? American Morse of International Morse? The North American
railroad telegraphers and Great Lakes radio operators used American Morse
and all the rest of us use Continental Morse.
--
Richard Loken VE6BSV, Unix System Administrator : "Anybody can be a father
Athabasca University : but you have to earn
Athabasca, Alberta Canada : the title of 'daddy'"
** richardlo at admin.athabascau.ca ** : - Lynn Johnston
12:37 p.m.
At 01:59 PM 11/5/2015, John Ball wrote:
... those bluetooth to cellular POTS bridges are too
lossy to make do and connect to a machine here.
There is strong possibility that one of those bridges might not work. As a rule the
bit-reduction used by cellular phones, VOIP phones, and cable-modem phones renders dialup
modems useless, unless you are using something like a fax-capable line.
I am developing (it is under construction to add additional features that I need) an
Arduino-based central office simulator that will allow two devices to connect to each
other as though connected by POTS lines. I began developing it to simplify work in the
shop on a variety of broadcast equipment that uses modems, as the only phone line at the
house is a cable-modem phone line that does not work with dialup modems.
If you had something of that sort I would think it possible to configure a computer to act
as the other end of the circuit.
Dale H. Cook, Roanoke/Lynchburg, VA
Osborne 1 / Kaypro 4-84 / Kaypro 1 / Amstrad PPC-640
http://plymouthcolony.net/starcity/radios/index.html
12:44 p.m.
On Nov 5, 2015, at 12:37 PM, Dale H. Cook
<radiotest at juno.com> wrote:
There is strong possibility that one of those bridges might not work. As a rule the
bit-reduction used by cellular phones, VOIP phones, and cable-modem phones renders dialup
modems useless, unless you are using something like a fax-capable line.
VoIP works fine, it's how I run my BBS. I've had calls connect from 300 to 33600.
I've got no analog land line, the modem is connected to an Asterisk PBX.
http://www.insentricity.com/a.cl/230/using-modems-without-phone-lines
I have had absolutely no luck getting modems to connect by sending audio through a cell
phone though.
--
Follow me on twitter: @FozzTexx
Check out my blog: http://insentricity.com
1:12 p.m.
I am developing (it is under construction to add additional features that I need) an
Arduino-based central office simulator that will allow two devices to connect to each
other as though connected by POTS lines. I began developing it to simplify work in the
shop on a variety of broadcast equipment that uses modems, as the only phone line
at the house is a cable-modem phone line that does not work with dialup modems.
Some time back I was thinking of making something similar, although to me it's just
a simple state machine and doesn't need a microcontroller. Heck, originally it was
done
by the telephone company using relays. I don't like using thousands of components
when
a couple of dozen will do :-) But the control circuit is the easy part, it's things
like the power
supplies, ringing generator, etc that are the major part of the work. The ringing voltage
in
particular is a pain, it's AC, and at a fairly low frequency (16.67Hz to 25Hz
depending on
country). Some devices, particular classic telephones with a mechanical ringer, do not
work correctly on a 50Hz or 60Hz ringing voltage taken from a mains transformer.
After sketching out a design, I realised that the cost of the main bits (line switching
relays,
the power supply for the ringing voltage, the 48V PSU for the line 'battery'
voltage, etc
was comparable to a cheap ready-build device to do much the same job. Of course
the ready-built one would be difficult to keep going so I probably wouldn't go that
route
But anyway, telephone line simulators do turn up on Ebay and I was lucky enough to find
a non-working one for (I think) $25. I figured that even if I couldn't fix it it would
contain
useful bits for power supplies, etc.
After fixing the mains switch and reseating the socketed ICs it sprang to life and almost
worked. After replacing a couple of LM311 comparators and a 3 terminal regulator it
was perfect.
This thing is _complicated_. IIRC there are 7 microprocessors/microcontrollers in it.
Around
400-500 ICs spread over 3 main PCBs and 7 smaller PCBs (some of which are just switches
or connectors). It does do a lot though, it will generate the correct call progress tones
and
ringing voltage for just about any countries system. It will deliberately introduce noise
(from a shift register with XOR feedback) or degrade the line (handled by a classic DSP
-- a TMS320 IIRC).
Do I need all that for fooling around with old telephones and modems? No. But it was
actually the cheapest solution and it is a nice, classic, piece of test gear.
-tony
6 Nov
6 Nov
5:11 a.m.
At 04:12 PM 11/5/2015, Tony Duell wrote:
... it's things like the power supplies, ringing
generator, etc that are the major part of the work.
Those are actually pretty simple for someone with sufficient analog experience. The
reasons why I designed and built my own system are:
1) I am semi-retired and have more time than money.
2) I had everything I needed in-house except for the call-progress generator IC (which was
easily obtained).
3) I enjoy designing and building equipment, though this is my first dedicated processor
build in more than 20 years.
The ringing voltage in particular is a pain, it's
AC, and at a fairly low frequency (16.67Hz to 25Hz depending on country).
In the US the Bell standard is a 90 VAC sine wave at 20 HZ with a cadence of 2 seconds on
and 4 seconds off. I work only with US equipment so I only have to meet Bell standards.
Dale H. Cook, Roanoke/Lynchburg, VA
Osborne 1 / Kaypro 4-84 / Kaypro 1 / Amstrad PPC-640
http://plymouthcolony.net/starcity/radios/index.html
5 Nov
5 Nov
4:03 p.m.
On 2015-Nov-05, at 10:59 AM, John Ball wrote:
I've been trying for the past week to verify that
telephony on my teletype
machine (model 33) is functioning properly but the biggest hurdle I am
running into is I have nothing to easily dial into. Everyone I know off hand
either don't have a modem anymore or theirs is a Winmodem which won't work.
There's only one phone line into the residence here and those bluetooth to
cellular POTS bridges are too lossy to make do and connect to a machine
here. There is that youtube video of the model 37 apparently connecting to a
system at the Living Computer Museum in 2013 (MikoF6KZjm0) where they dialed
into a BBS I've never seen listed anywhere but the number listed no longer
seems to work and in the description it states the service is no longer
available. What other public systems are still out there that will work this
speed or possibly better yet, is there anyone out there willing to try a
teletype-to-teletype conversation?
Curious as to the setup you are attempting this with, i.e. exactly what modem are you
using?
One in the base of the 33 or some common external one?
I'm not familiar with all the possible modem variations one might find in a 33, but
AIUI the modem for the 33 at the standard 110 bps was Bell 101 standard.
There's not going to be a lot to talk to out there using the old parameters.
Even if someone had an auto-baud dial-in setup out there somewhere, I wouldn't
anticipate it being compatible.
We have a 101-standard modem (in the base of a 33) around here, but have never tried it or
tried connecting it to a phone line, I'm also not familiar with it enough to know how
originate/answer issues are dealt with (whether it can do both) for such 33 to 33
communication.
4:13 p.m.
On Thursday (11/05/2015 at 04:03PM -0800), Brent Hilpert wrote:
Curious as to the setup you are attempting this with, i.e. exactly what modem are you
using?
One in the base of the 33 or some common external one?
I'm not familiar with all the possible modem variations one might find in a 33, but
AIUI the modem for the 33 at the standard 110 bps was Bell 101 standard.
There's not going to be a lot to talk to out there using the old parameters.
Even if someone had an auto-baud dial-in setup out there somewhere, I wouldn't
anticipate it being compatible.
We have a 101-standard modem (in the base of a 33) around here, but have never tried it
or tried connecting it to a phone line, I'm also not familiar with it enough to know
how originate/answer issues are dealt with (whether it can do both) for such 33 to 33
communication.
Highest likelihood it is a Bell 103 which is AFSK at 300 baud or less.
The problem you have with Teletype to Teletype with telephone modems is
that both ends are likely to be originate modems-- meaning they will
have the same tone pairs for transmitting and receiving and thus cannot
talk to each other.
One end needs to be Originate (which is the Teletype) and the other end
needs to be Answer with the opposite tone pairs-- so that the transmit
tones are received by the other side and vise-versa.
https://en.wikipedia.org/wiki/Bell_103_modem
Some very old acoustic couplers did have a way to reverse the tone pairs
but they were not very common.
--
Chris Elmquist
6 Nov
6 Nov
7:24 a.m.
On Thu, Nov 5, 2015 at 7:03 PM, Brent Hilpert <hilpert at cs.ubc.ca> wrote:
On 2015-Nov-05, at 10:59 AM, John Ball wrote:
When I got an ASR33 with a built-in dataset (from the Dayton Hamfest,
in the 80s), I had much the same quandry. At the time, my best
solution was to call up a local CompuServe number. I got a login
prompt and called it good.
That said, I'd be a little surprised if that trick still worked.
-ethan
I've been trying for the past week to verify
that telephony on my teletype
machine (model 33) is functioning properly but the biggest hurdle I am
running into is I have nothing to easily dial into...
I'm not familiar with all the possible modem variations one might find in a 33, but
AIUI the modem for the 33 at the standard 110 bps was Bell 101 standard.
5 Nov
5 Nov
4:07 p.m.
On Thursday (11/05/2015 at 10:59AM -0800), John Ball wrote:
I've been trying for the past week to verify that
telephony on my teletype
machine (model 33) is functioning properly but the biggest hurdle I am
running into is I have nothing to easily dial into. Everyone I know off hand
either don't have a modem anymore or theirs is a Winmodem which won't work.
There's only one phone line into the residence here and those bluetooth to
cellular POTS bridges are too lossy to make do and connect to a machine
here. There is that youtube video of the model 37 apparently connecting to a
system at the Living Computer Museum in 2013 (MikoF6KZjm0) where they dialed
into a BBS I've never seen listed anywhere but the number listed no longer
seems to work and in the description it states the service is no longer
available. What other public systems are still out there that will work this
speed or possibly better yet, is there anyone out there willing to try a
teletype-to-teletype conversation?
If you have a "Smart Modem" (ie, stand alone unit with serial port)
you can connect it to the modem in the Teletype with a battery-- like,
a 9V battery-- in series with the phone line between the two. Then you
use the Teletype modem to place a call to any random number and command
the Smart Modem to go off-hook with "ATA". This will cause it to
generate answer tones and the Teletype originate modem will "connect"
and off you go.
You don't need a ring generator or any ring voltage on the line since you
can manually command the Smart Modem at the answer end to answer with the
"ATA" command.
I pretty much ignored "WinModems" in the day but I would think that
if they can do answer mode, this approach would work with one of those
as well. Open the terminal app on the Windows box in which this WinModem
is installed and simply enter "ATA" to cause it to go off-hook in answer
mode. If the 9V battery is in series with the line to the modem in the
Teletype, you should be good. There might be polarity issues so reverse
the battery if it doesn't work the first time.
Chris
--
Chris Elmquist
6 Nov
6 Nov
12:51 a.m.
On Thu, 5 Nov 2015, Chris Elmquist wrote:
Why don't you suggest the easiest and obvious: use a small analog PBX.
There are _plenty_ of them floating around, and most can be had for free;
you could for example even use your FritzBox Phone (a DSL WiFi Router with
analog phone ports). Then you can do internal calls from one port to any
other port (and also use your old rotary dial phone with VoIP if you
like).
Christian
On Thursday (11/05/2015 at 10:59AM -0800), John Ball
wrote:
> I've been trying for the past week to verify that telephony on my teletype
> machine (model 33) is functioning properly but the biggest hurdle I am
> running into is I have nothing to easily dial into. Everyone I know off hand
> either don't have a modem anymore or theirs is a Winmodem which won't work.
> There's only one phone line into the residence here and those bluetooth to
[...]
speed or
possibly better yet, is there anyone out there willing to try a
teletype-to-teletype conversation?
If you have a "Smart Modem" (ie,
stand alone unit with serial port)
you can connect it to the modem in the Teletype with a battery-- like,
a 9V battery-- in series with the phone line between the two. Then you
use the Teletype modem to place a call to any random number and command
the Smart Modem to go off-hook with "ATA". This will cause it to
generate answer tones and the Teletype originate modem will "connect"
and off you go.
3334
days inactive
3335
days old
14 comments
11 participants
participants (11)
-
ard＠p850ug1.demon.co.uk -
ball.of.john＠gmail.com -
cc＠informatik.uni-stuttgart.de -
chrise＠pobox.com -
cisin＠xenosoft.com -
ethan.dicks＠gmail.com -
fozztexx＠fozztexx.com -
hilpert＠cs.ubc.ca -
other＠oryx.us -
radiotest＠juno.com -
richardlo＠admin.athabascau.ca