Re: Does anyone remember the IMTS System? [telecom]

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

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.

I couldn't resist: I copied the "Organization" header into the text.

Bill Horne Moderator

Just once:

sox -V -r 48000 -n -b 16 -c 2 imts-disconnect.wav \ synth .05 sine 1336 vol -10db \ : synth .05 sine 1800 vol -10db \ : synth .05 sine 1633 vol -10db

You should be able to do that with sox too. Check the man page.

--scott

Here's an excellent site that covers both "MJ" (VHF) and "MK" (UHF) IMTS Systems ...