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Does anyone remember the IMTS System? [telecom]
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Bill Horne
May 21, 2015, 7:43:36 PM5/21/15
to
Here's a trip down memory lane: does anyone remember the IMTS
systems that preceded cellular? I find myself getting nostalgic
for the "good old days" of the mobile world, and I wonder if
any of that equipment has been converted to other uses.
Bill
(Remove QRM from my address to write to me directly)
systems that preceded cellular? I find myself getting nostalgic
for the "good old days" of the mobile world, and I wonder if
any of that equipment has been converted to other uses.
Bill
(Remove QRM from my address to write to me directly)
HAncock4
May 22, 2015, 10:45:44 AM5/22/15
to
On Thursday, May 21, 2015 at 7:43:36 PM UTC-4, Bill Horne wrote:
> Here's a trip down memory lane: does anyone remember the IMTS
> systems that preceded cellular?
In the early 1970s, a friend of mine worked for a VIP who had
> Here's a trip down memory lane: does anyone remember the IMTS
> systems that preceded cellular?
a mobile phone in his car. My friend would call me or I would
call him on it occasionally. We kept our calls brief as it
was expensive.
Operationally, it worked like a regular telephone; the mobile set
had a rotary dial and a ringer.
Certain elite passenger trains, like the 20th Century Limited,
Broadway Limited, and Congressionals had on-board mobile
telephone service, though I believe it was the older manual type.
Metroliner service, introduced in 1969, had a modern on-board mobile
phone, with automatic handoff between radio bases, and Touch Tone
coin telephone sets. If memory serves, a call was priced at $3.00
for three minutes, high in its day, but not outrageous. (FWIW,
when I rode a Metroliner train in 1973, no one used the phone.)
> I find myself getting nostalgic
> for the "good old days" of the mobile world, and I wonder if
> any of that equipment has been converted to other uses.
an _automobile_ telephone--one could only use it in their car.
It seems that a great many cell phone users today would find
that restriction extremely limiting. (Ironically today,
such use while driving is illegal in some places.)
Also, the phone took up space, both the dashboard unit and a unit
in the trunk.
When cellular phones first came out, they were automobile-
oriented, and cell phone stores had a garage to physically
mount the phone in the car.
We also must remember that capacity was extremely limited,
there was room for only a few conversations at time. The
Bell System regularly sought more radio channels, but was
denied by the FCC.
>From the Bell Labs Switching history:
"The crossbar tandem system was used to serve these mobile
and other special service lines directly--a function it
could perform since it could receive and send dial pulses."
"Significant use of private mobile radio systems dates back to 1921,
beginning with the Detroit police department. Over the years, the
Federal Communications Commission has granted additional radio
spectra to increase private licenses to over eight million users (and
another eight million on CB). These systems for the most part do
not connect to the telephone network. Beginning in 1946, the Bell
System inaugurated a three-channel system in St. Louis. Over the
succeeding years, additional frequencies were allocated, improvements
were made in changing service from manual to automatic,
and trunking was added between mobile units and available channels.
However, only 143,000 customers are served by Bell and the
radio common carriers (RCC). There are tens of thousands of held
orders for carrier-connected mobile telephone systems, even though
the tariff is ten to twenty times that of residential telephone service.
Because the waiting time is so long, there are many others who need
this type of service but have not bothered to add themselves to the
waiting list."
[evolution to cell service]
"Since 1947, the Bell System has expressed to the Federal
Communications Commission, in a number of review dockets, its
interest in a large-scale mobile telephone system. In docket 19262,
Bell introduced in 1971 a new version of the cellular system, which
reuses a basic group of frequencies in nonadjacent hexagonal cells.
As the mobile unit roams from cell to cell, its connection is moved
from transceiver to transceiver under control of a central office
switching system. No. 1 ESS was chosen to be the mobile telephone
switching office (MTSO), since it has the software capability to allocate
cells and frequencies as a call is "handed off" from cell to cell.
In addition, the MTSO has to locate the cell for originations and provide
additional conveniences for mobile customers. Initially the
intent was to combine local and mobile services in the same switching
office. In 1975, the FCC gave the Bell System the go-ahead for a
development field trial of the cellular system but the switching
office would be limited to handling only calls to and from mobile
units. A No. 1 ESS, located in Oakbrook, Illinois was set up to
operate a few cells and mobile units. Success of the trial is expected
to lead to a larger service test and, with FCC approval, commercial
service. "
tlvp
May 22, 2015, 10:45:44 AM5/22/15
to
On Thu, 21 May 2015 19:38:19 -0400 EDT, Bill Horne wrote:
> Here's a trip down memory lane: does anyone remember the IMTS
> systems that preceded cellular? I find myself getting nostalgic
> for the "good old days" of the mobile world, and I wonder if
> any of that equipment has been converted to other uses.
I can't say I "remember" it, but Google certainly responds to the IMTS bait
> Here's a trip down memory lane: does anyone remember the IMTS
> systems that preceded cellular? I find myself getting nostalgic
> for the "good old days" of the mobile world, and I wonder if
> any of that equipment has been converted to other uses.
and offers this neat catch (amongst others)
<http://en.wikipedia.org/wiki/Improved_Mobile_Telephone_Service>
for your delectation :-) . Cheers, -- tlvp
--
Avant de repondre, jeter la poubelle, SVP.
John Levine
May 22, 2015, 10:45:44 AM5/22/15
to
>Here's a trip down memory lane: does anyone remember the IMTS
>systems that preceded cellular?
I went to a church camp on an island off the coast of New Hampshire
>systems that preceded cellular?
where for many years the only phone was an IMTS phone installed in a
phone booth in the lobby. To call in, you'd dial 0, ask for the
mobile operator in Dover NH, then ask the operator for JS8-3445. (The
phone had a dial but my recollection is that they never automated that
mobile site.) Calls were expensive and limited to three minutes.
When IMTS shut down one of the campers who was an engineer in real
life put an antenna on the roof with line of sight to a church steeple
on the mainland and set up a remote phone repeater, which gave us a
pair of normal phones with normal phone numbers, albeit somewhat hissy
sound. Since then I gather they arranged to run a cable to an
adjacent island where the Coast Goard had run a cable out to their
lighthouse from the mainland, and now they have not just phone but
Internet. The campers, of course, just use their cell phones to cell
sites on the mainland since radio waves propagate easily across salt
water.
R's,
John
danny burstein
May 23, 2015, 12:27:18 AM5/23/15
to
[snip]
They were, of course, Expensive Toys for the Rich and Famous.
As such, in the tv show Superman (the real one in the 1950s,
accept no imitiation), Perrry White had one. None of the
reporters or other staffers did..
--
_____________________________________________________
Knowledge may be power, but communications is the key
dan...@panix.com
[to foil spammers, my address has been double rot-13 encoded]
They were, of course, Expensive Toys for the Rich and Famous.
As such, in the tv show Superman (the real one in the 1950s,
accept no imitiation), Perrry White had one. None of the
reporters or other staffers did..
--
_____________________________________________________
Knowledge may be power, but communications is the key
dan...@panix.com
[to foil spammers, my address has been double rot-13 encoded]
HAncock4
May 26, 2015, 8:33:18 PM5/26/15
to
On Thursday, May 21, 2015 at 7:43:36 PM UTC-4, Bill Horne wrote:
> Here's a trip down memory lane: does anyone remember the IMTS
> systems that preceded cellular? I find myself getting nostalgic
> for the "good old days" of the mobile world, and I wonder if
> any of that equipment has been converted to other uses.
P.S.
> systems that preceded cellular? I find myself getting nostalgic
> for the "good old days" of the mobile world, and I wonder if
> any of that equipment has been converted to other uses.
Some additional early cellular telphone history:
In 1984, the Western Union Telegraph Company, along with its partners,
operated cell phone service in Buffalo, Indianapolis, and Milwaukee as
the non-wireline carrier. Construction was underway in Cleveland,
Detroit, and Toledo. Telephone sets were manufactured by WU's
subsidiary, E. F. Johnson.
WU also operated, along with Goeken Communications, Airfone service,
with phones in 15 widebody planes, and 100 expected by year end.
They handled 150 calls per day. E. F. Johnson also manufactured
the Airfone equipment.
In addition, in 1984 WU offered long distance voice service. WU said
a six minute daytime call from NYC to L.A. would cost $3.00 via AT&T,
$2.83 via GTE, $2.67 via MCI, and $2.64 via WU. WU claimed its
voice long distance rates were 25% cheaper than AT&T between points
served by WU's microwave system, and 15% cheaper between other points.
In those years, WU was Fighting very substantial rate increases
from local telephone companies for local loop access lines to
subscribers for data and teletypewriter services. Though WU had
been migrating such traffic over to its own lines, a considerable
part remained. For instance, after WU acquired AT&T's TWX system,
WU had to move all the subscribers over its own lines and switching
systems.
--Western Union News, July 1984, August 1984, November 1984.
***** Moderator's Note *****
Western Union's move of TWX to "it's own lines and offices" took a
great deal of time: I worked in the Boston-2 test center in the 80's,
and we had a "WADS" office there, which was a #5 Crossbar switch that
handled TWX. There were contracted TWX and Telex lines right up to the
time when I was promoted into NYNEX IS in 1989.
Bill Horne
Moderator
New Reader
Apr 18, 2018, 8:29:39 PM4/18/18
to
On Thursday, May 21, 2015 at 4:43:36 PM UTC-7, Bill Horne wrote:
> Here's a trip down memory lane: does anyone remember the IMTS
> systems that preceded cellular? I find myself getting nostalgic
> for the "good old days" of the mobile world, and I wonder if
> any of that equipment has been converted to other uses.
I had a number of Motorola IMTS systems in my trucks. Also GE. All on
> Here's a trip down memory lane: does anyone remember the IMTS
> systems that preceded cellular? I find myself getting nostalgic
> for the "good old days" of the mobile world, and I wonder if
> any of that equipment has been converted to other uses.
vhf band. I have a GE IMTS phone with Glenayre head that still works.
***** Moderator's Note *****
does the service cost?
By the way, there's an excellent site covering the pre-cellular mobile
phones:
http://www.wb6nvh.com/Carphone.htm
Bill Horne
Moderator
HAncock4
Apr 22, 2018, 11:52:47 AM4/22/18
to
On Thursday, May 21, 2015 at 7:43:36 PM UTC-4, Bill Horne wrote:
> Here's a trip down memory lane: does anyone remember the IMTS
> systems that preceded cellular? I find myself getting nostalgic
> for the "good old days" of the mobile world, and I wonder if
> any of that equipment has been converted to other uses.
Here is an old ad:
> systems that preceded cellular? I find myself getting nostalgic
> for the "good old days" of the mobile world, and I wonder if
> any of that equipment has been converted to other uses.
http://www.telephonecollectors.info/index.php/browse/catalogs-manuals-educational-docs-by-company/other-manufacturers/3712-motorola-imts-ad-improved-mobile-telephone-system
Here is a Bell Labs Record article on the Metroliner system:
http://www.telephonecollectors.info/index.php/browse/catalogs-manuals-educational-docs-by-company/western-electric-bell-system/publications-and-educational-documents-by-date/blr/11618-69mar-blr-p77-metroliner-train-telephones
Here is a Bell Labs Record article on the 1953 railroad mobile
telephone:
http://www.telephonecollectors.info/index.php/browse/document-repository/catalogs-manuals/western-electric/bell-labs-record/11421-53sep-blr-p342-trains-payphone
***** Moderator's Note *****
And ... OMG, is that Pre-Progress Line equipment I see in the picture? I used to fix those!
Bill Horne
Moderator
John Levine
Apr 23, 2018, 5:09:00 PM4/23/18
to
In article <20150521234...@telecom.csail.mit.edu> On
NH. The original high-speed communication to and from the mainland
was carrier pigeons, which would fly out in the morning to tell the
kitchen how many people to expect for lunch on the noon boat. When we
started going in the 1960s and 1970s they had an IMTS phone mounted in
an old phone booth. You'd call them by dialing the operator, asking
for the mobile operator in Dover NH, and asking her for JS8-3445. (I
don't think that fairly rural exchange ever implemented IMTS dialing.)
The operators never could understand that this phone did not move, and
if they weren't answering it was not because they had driven out of
range.
At some point one of the engineers who attended the conferences
brought out a point to point phone repeater, with the antennae in the
top of the island hotel and the steeple of a church on the mainland.
That worked pretty well, so the IMTS phone went away in favor of a
POTS phone with a normal phone number.
In the 1980s we started bringing out our cell phones and although ten
miles from a tower is a long way, line of sight over salt water is
ideal for propagation so they worked OK. Around that time the Coast
Guard automated the lighthouse on a nearby island and in the process
ran a cable out to that island, and let us piggyback on that, so now
if you know where to look, there's Ethernet cables in some of the
buildings on the island that connect to the Internet.
R's,
John
***** Moderator's Note *****
John, if you already had the roost, why not just switch to RFC1149? ;-)
Bill Horne
Moderator
Thursday, May 21, 2015 at 7:43:36 PM UTC-4, Bill Horne wrote:
> Here's a trip down memory lane: does anyone remember the IMTS
> systems that preceded cellular?
We used to go to a church camp on an island ten miles off Portsmouth
> systems that preceded cellular?
NH. The original high-speed communication to and from the mainland
was carrier pigeons, which would fly out in the morning to tell the
kitchen how many people to expect for lunch on the noon boat. When we
started going in the 1960s and 1970s they had an IMTS phone mounted in
an old phone booth. You'd call them by dialing the operator, asking
for the mobile operator in Dover NH, and asking her for JS8-3445. (I
don't think that fairly rural exchange ever implemented IMTS dialing.)
The operators never could understand that this phone did not move, and
if they weren't answering it was not because they had driven out of
range.
At some point one of the engineers who attended the conferences
brought out a point to point phone repeater, with the antennae in the
top of the island hotel and the steeple of a church on the mainland.
That worked pretty well, so the IMTS phone went away in favor of a
POTS phone with a normal phone number.
In the 1980s we started bringing out our cell phones and although ten
miles from a tower is a long way, line of sight over salt water is
ideal for propagation so they worked OK. Around that time the Coast
Guard automated the lighthouse on a nearby island and in the process
ran a cable out to that island, and let us piggyback on that, so now
if you know where to look, there's Ethernet cables in some of the
buildings on the island that connect to the Internet.
R's,
John
***** Moderator's Note *****
Bill Horne
Moderator
Antenna Man
Sep 5, 2021, 5:09:04 PM9/5/21
to
On Thursday, May 21, 2015 at 7:43:36 PM UTC-4, Bill Horne wrote:
> Here's a trip down memory lane: does anyone remember the IMTS
> systems that preceded cellular? I find myself getting nostalgic
> for the "good old days" of the mobile world, and I wonder if
> any of that equipment has been converted to other uses.
>
> Bill
Hi Bill,
> systems that preceded cellular? I find myself getting nostalgic
> for the "good old days" of the mobile world, and I wonder if
> any of that equipment has been converted to other uses.
>
> Bill
I regularly get into conversations with 30 or 40-ish year olds that like to
talk about the 'history' of mobile telephones. Their 'history' is the 3 watt
bag phone that their dad had. They don't know there was 30 years of IMTS and
before that MTS before the first AMPS trials in Chicago. I try to explain,
but they get blank looks on their faces.
I got my first IMTS phone in about 1975.....a 25 watt UHF Motorola "Green
Weenie" trunk mount radio with a FACTS control head. Loved that thing. I had
an employee at the time that just LOVED to switch to manual mode and listen to
other conversations if he was waiting in my truck. He discovered that if we
were parked close enough to a voting receiver location, he could manually key
up and become the 'mobile' of the conversation. Shame on him.
I've been looking for a function generator app from which I can cut a ringtone
or notification tone that has the alternating 1336 and 1800 Hz IMTS
"disconnect" tones that the IMTS mobile would send out to the base when the
mobile was 'hung up'. A second or two of it would play out over the circuit
to the landline caller before the terminal disconnected him. I always liked
that signal, and would like to have it as a notification or ring tone for some
special old friends from my IMTS days.
Scott Dorsey
Nov 2, 2021, 11:00:06 AM11/2/21
to
Antenna Man <ken...@gmail.com> wrote:
>I've been looking for a function generator app from which I can cut a
>ringtone or notification tone that has the alternating 1336 and 1800
>Hz IMTS "disconnect" tones that the IMTS mobile would send out to the
>base when the mobile was 'hung up'. A second or two of it would play
>out over the circuit to the landline caller before the terminal
>disconnected him. I always liked that signal, and would like to have
>it as a notification or ring tone for some special old friends from
>my IMTS days.
You should be able to manually generate 1336 and 1800 tones with
>I've been looking for a function generator app from which I can cut a
>ringtone or notification tone that has the alternating 1336 and 1800
>Hz IMTS "disconnect" tones that the IMTS mobile would send out to the
>base when the mobile was 'hung up'. A second or two of it would play
>out over the circuit to the landline caller before the terminal
>disconnected him. I always liked that signal, and would like to have
>it as a notification or ring tone for some special old friends from
>my IMTS days.
Audacity and edit them together.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Bill Horne
Nov 3, 2021, 11:01:29 AM11/3/21
to
On Tue, Nov 02, 2021 at 03:27:34PM -0000, Marc SCHAEFER wrote:
> Antenna Man <ken...@gmail.com> wrote:
> >I've been looking for a function generator app from which I can cut a
> >ringtone or notification tone that has the alternating 1336 and 1800
> >Hz IMTS "disconnect" tones that the IMTS mobile would send out to the
> >base when the mobile was 'hung up'. A second or two of it would play
>
> Simple generation:
> Antenna Man <ken...@gmail.com> wrote:
> >I've been looking for a function generator app from which I can cut a
> >ringtone or notification tone that has the alternating 1336 and 1800
> >Hz IMTS "disconnect" tones that the IMTS mobile would send out to the
> >base when the mobile was 'hung up'. A second or two of it would play
>
>
> sox -V -r 48000 -n -b 16 -c 2 imts-disconnect.wav synth 30 sin 1336 sin 1800 vol -10dB
>
> The file is on:
>
> https://login.alphanet.ch/~schaefer/tmp/imts-disconnect.wav
>
> You could then adapt the sox command line for your needs.
I remember that the IMTS phones that used VHF channels had push-
buttons that allowed users to access the older manual system:
they could press a push-to-talk button that was part of the handset,
and draw the attention of a mobile operator who would ask for their
mobile id, which consisten of a "Home" channel, followed by their call
signalling code, followed by the city of registry (mine was JL-36446,
San Francisco).
When a manual system was cut over form "MTS" to IMTS, the units were
rewired so that they would respond to an ID made up of the area code
and last four digits of the associated POTS number: a design choice
that limited IMTS to fewer than 10,000 users per area code, per radio
band
UHF units, which were never used for "manual" service, had much
smaller control heads, which looked like overgrown Princess phones.
Bill
--
Bill Horne
(Remove QRM from my email address to write to me directly)
Marc SCHAEFER
Nov 3, 2021, 11:01:29 AM11/3/21
to
Antenna Man <ken...@gmail.com> wrote:
>I've been looking for a function generator app from which I can cut a
>ringtone or notification tone that has the alternating 1336 and 1800
>Hz IMTS "disconnect" tones that the IMTS mobile would send out to the
>base when the mobile was 'hung up'. A second or two of it would play
>I've been looking for a function generator app from which I can cut a
>ringtone or notification tone that has the alternating 1336 and 1800
>Hz IMTS "disconnect" tones that the IMTS mobile would send out to the
>base when the mobile was 'hung up'. A second or two of it would play
Jay Hennigan
Nov 11, 2021, 10:07:06 AM11/11/21
to
Organization: Disgruntled Postal Workers Against Gun Control
Not quite. The tones alternate at 20 pulses per second, not
simultaneous. 1336 for 50ms, then 1800 for 50 ms, then 1633 for 50 ms,
etc.
***** Moderator's Note *****
I couldn't resist: I copied the "Organization" header into the text.
Bill Horne
Moderator
simultaneous. 1336 for 50ms, then 1800 for 50 ms, then 1633 for 50 ms,
etc.
***** Moderator's Note *****
Bill Horne
Moderator
Marc SCHAEFER
Nov 11, 2021, 11:00:40 AM11/11/21
to
Jay Hennigan <nob...@example.com.invalid> wrote:
>> You could then adapt the sox command line for your needs.
>
> Not quite. The tones alternate at 20 pulses per second, not
> simultaneously. 1336 for 50ms, then 1800 for 50 ms, then 1633 for 50
>> You could then adapt the sox command line for your needs.
>
> Not quite. The tones alternate at 20 pulses per second, not
> ms, etc.
Just once:
sox -V -r 48000 -n -b 16 -c 2 imts-disconnect.wav \
: synth .05 sine 1800 vol -10db \
: synth .05 sine 1633 vol -10db
Scott Dorsey
Nov 20, 2021, 11:44:51 PM11/20/21
to
Jay Hennigan <nob...@example.com.invalid> wrote:
>Organization: Disgruntled Postal Workers Against Gun Control
>
>On 2021-11-02 15:27:34 +0000, Marc SCHAEFER said:
>
>> Simple generation:
>>
>> sox -V -r 48000 -n -b 16 -c 2 imts-disconnect.wav synth 30 sin 1336
>> sin 1800 vol -10dB
>>
>> The file is on:
>>
>> https://login.alphanet.ch/~schaefer/tmp/imts-disconnect.wav
>>
>> You could then adapt the sox command line for your needs.
>
> Not quite. The tones alternate at 20 pulses per second, not
> simultaneous. 1336 for 50ms, then 1800 for 50 ms, then 1633 for 50
> ms,
You should be able to do that with sox too. Check the man page.
>Organization: Disgruntled Postal Workers Against Gun Control
>
>On 2021-11-02 15:27:34 +0000, Marc SCHAEFER said:
>
>> Simple generation:
>>
>> sox -V -r 48000 -n -b 16 -c 2 imts-disconnect.wav synth 30 sin 1336
>> sin 1800 vol -10dB
>>
>> The file is on:
>>
>> https://login.alphanet.ch/~schaefer/tmp/imts-disconnect.wav
>>
>> You could then adapt the sox command line for your needs.
>
> Not quite. The tones alternate at 20 pulses per second, not
> simultaneous. 1336 for 50ms, then 1800 for 50 ms, then 1633 for 50
> ms,
Moderator
Nov 20, 2021, 11:44:51 PM11/20/21
to
On Thursday, May 21, 2015 at 4:43:36 PM UTC-7, Bill Horne wrote:
> Here's a trip down memory lane: does anyone remember the IMTS
> systems that preceded cellular? I find myself getting nostalgic
> for the "good old days" of the mobile world, and I wonder if
> any of that equipment has been converted to other uses.
Here's an excellent site that covers both "MJ" (VHF) and "MK" (UHF)
> Here's a trip down memory lane: does anyone remember the IMTS
> systems that preceded cellular? I find myself getting nostalgic
> for the "good old days" of the mobile world, and I wonder if
> any of that equipment has been converted to other uses.
IMTS Systems ...
http://www.wb6nvh.com/MTSfiles/Carphone5.htm
--
Bill Horne
Telecom Digest Moderator
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