Hello John ... and Mike ...
The Motorola Mocom-10 Manual, part number 68P81010E40, dated
7/17/70, covered the following model numbers:
Dash-mount mobile radio Models ... 12 VDC, Negative ground
D21AAN-1100B Carrier Squelch
D21AAN-3100B "Private Line" Tone-Coded Squelch
D21AAN-5100B "Automute" Tone-Coded Squelch
D31AAN-1100B Carrier Squelch
D31AAN-3100B "Private Line" Tone-Coded Squelch
D31AAN-5100B "Automute" Tone-Coded Squelch
D31AAN-1130B Two-Frequency Carrier Squelch
D31AAN-3130B Two-Frequency "Private Line" Tone-Coded Squelch
D41AAN-1100B Carrier Squelch
D41AAN-3100B "Private Line" Tone-Coded Squelch
D41AAN-5100B "Automute" Tone-Coded Squelch
D41AAN-1130B Two-Frequency Carrier Squelch
D41AAN-3130B Two-Frequency "Private Line" Tone-Coded Squelch
Desk Top Base Station Models ... 117 VAC
L21AAB-1100B Carrier Squelch
L21AAB-3100B "Private Line" Tone-Coded Squelch
L21AAB-5100B "Automute" Tone-Coded Squelch
L31AAB-1100B Carrier Squelch
L31AAB-3100B "Private Line" Tone-Coded Squelch
L31AAB-5100B "Automute" Tone-Coded Squelch
L31AAB-1130B Two-Frequency Carrier Squelch
L31AAB-3130B Two-Frequency "Private Line" Tone-Coded Squelch
L41AAB-1100A Carrier Squelch
L41AAB-3100A "Private Line" Tone-Coded Squelch
L41AAB-5100A "Automute" Tone-Coded Squelch
L41AAB-1130A Two-Frequency Carrier Squelch
L41AAB-3130A Two-Frequency "Private Line" Tone-Coded Squelch
D/L21 Series Radio sets are 1.5 watts out
D/L31 Series Radio sets are 5 watts out
D/L41 Series Radio sets are 25 watts out
The Automute Tone-Coded Squelch is very similar to the Single-Tone
coded squelch systems of the late fifties / early sixties. The
normally used "Automute" Tone frequencies are listed as follows:
Automute Frequency
Code (CPS)
01 625
02 735
03 825
04 900
05 980
06 1070
07 1170
08 1280
09 1400
10 1520
11 1650
12 1800
13 1950
14 2100
15 2250
16 2400
17 2610
18 2840
The receiver is muted to all incoming messages except those with
the correct "Automute" tone code. When the correct tone code is
received, the receiver is unmuted, a brief tone is heard, and the
amber signal light turns on. The receiver remains unmuted for the
duration of the transmission and the signal light remains on until
the microphone is lifted from the hang-up box.
When the operator lifts the microphone from the hang-up box, the
tone squelch circuit is automatically disabled so that the channel
may be monitored before transmitting. When the transmit button on
the microphone is pressed, the radio transmits a short audible tone
which is simultaneously reproduced by the speaker. After the tone
ceases, the operator speakes into the microphone. On succeeding
transmissions the tone is not transmitted unless the microphone is
returned to the hang-up box which resets the tone sending circuit.
(Thank you Motorola for the description.)
CHP (CHiP) = California Highway Patrol
Hope this helps,
Neil - WA6KLA
JOHN MACKEY wrote:
>
> I forget now, exactly WHAT was the "Automute" in the Mocom-10?
>
> While finding a motrac or motran mobile with the tone burst isn't
> to rare to find, expecially if you can latch into a bunch of retired
> CHiP gear. But finding tone burst DECODE is tough.
>
> About 15 years ago I put up a 6 meter repeater in Oregon. Due to
> the commonality amateurs having CHiP Motrans (that have tone burst
> built into the control head), I put a 1800 Hz tone burst decoder in
> parallel with the 100 Hz PL decoder for my repeater input. That
> way a user could access the repeater with either an 1800 Hz tone
> burst at the beginning of every transmission OR a 100 Hz PL tone.
>
> CHiP = California Highway Police
>
> ------ Original Message ------
> Received: Sun, 05 Dec 2004 09:58:24 PM CST
> From: Neil McKie <[EMAIL PROTECTED]>
> SNIP
> > The AutoMute system was usually installed on the Mocom-10 radios.
> >
> > Motorola also had tone burst on the tubed equipment as well as
> > the Motrac Line as an option.
>
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