Message-ID: <20211103142441.GA18880@telecom.csail.mit.edu>
Date: Wed, 3 Nov 2021 14:24:41 +0000
From: Bill Horne <malQassRimiMlation@gmail.com>
Subject: Re: Does anyone remember the IMTS System?
On Tue, Nov 02, 2021 at 03:27:34PM -0000, Marc SCHAEFER wrote:
> Antenna Man <kenpda@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:
>
> 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)
Message-ID: <slrld6$1i2$1@shakotay.alphanet.ch>
Date: 2 Nov 2021 15:27:34 -0000
From: "Marc SCHAEFER" <schaefer@alphanet.ch>
Subject: Re: Does anyone remember the IMTS System?
Antenna Man <kenpda@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:
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.
