[ICOM] Tone squelch operation, "uniformed" question - REPLY

[Tad Danley]

Yep, I spoke to plenty of Motorola community repeater customers back then who were upset and said 'I dont share frequencies with anyone, I have a Private Line!'

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Tad Danley, K3TD
EM10dq


-------- Original message --------
Subject: Re: [ICOM] Tone squelch operation, "uniformed" question - REPLY 
From: D C *Mac* Macdonald <k2gkk at hotmail.com> 
To: Icom Forum <icom at mailman.qth.net> 
CC:  


PL (Private Line) is simply Motorola's tradename for C.T.C.S.S. 
Don't know that Motorola "invented" it. 

GE named it Channel Guard (CG) and RCA called it Quiet Channel (QC). 

I worked on 'em all at Black Radio (W5JCB - SK) here in OKC for ~9 years. 

* * * * * * * * * * * 
* 73 - Mac, K2GKK/5 * 
* k2gkk at hotmail.com * 
* (Since 30 Nov 53) * 
* Oklahoma City, OK * 
* USAF, Ret (61-81) * 
* * * * * * * * * * * 



> Date: Tue, 14 Feb 2012 15:39:39 -0500
> From: lmairs at sagcorp.com
> To: icom at mailman.qth.net
> Subject: Re: [ICOM] Tone squelch operation, "uniformed" question - REPLY
> 
> Thanks for the trip down memory lane. My first FM rig came out of 
> somebody's taxi.
> 73 de Lee
> KM4YY
> 
> On 2/14/2012 12:19 PM, r morris wrote:
> > Back in the olden days, before cell phones, and before Icom and Kenwood, Motorola, GE and RCA made lots of money selling two way radios in the commercial world. The "community repeater". A single freq repeater with an auto multi PL select. The game also worked on a simplex freq. Sell a base station to Joe the plumber, Fred's TV repair, Jack the heating guy, put a mobile in his truck and mic and telephone in front of the wife. Since there are only so many channels, put a bunch all on the same freq with different PL. What's PL, Private Line, a sales and technical gimmick, fixing it so Joe does not have to listen to Fred.
> >
> > The FCC rule, in the commercial world, was you had to "monitor" the freq before making a call. Most of microphones had a metal hangup thingy on the back and the "hook" on the dash was grounded. When you picked up the mic it went off ground and switched off Rx PL, hence "monitoring" the channel. Most radios had a "monitor" button on the front. My Kenwood TH6 HT has one one the side.
> > An easy way to do it with today's radios, is put the same frequency in more than one memory with one, no PL, one for your buddies, one for your wife. Switch to M1 (no PL), make the polite call, is anyone using the freq, switch to M2, or M3 to open who ever's Rx.
> > How do you think ham FM and repeaters got started. All the old junk that got traded in when Joe got sucked into new radios or the local police traded up. Don't ask how I know this.....
> >
> > P.S. PL was copyrighted by Motorola and developed it, the rest of the world had to call it CTCSS, continuous tone coded squelch.
     
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