Dennis,
Motorola was several years ahead of any other company that used the Continuous Tone Coded Squelch System. All of my materials from Motorola (I was a Motorola dealer/ shop) even state that the tone keeps the squelch quiet so that the user does not hear all other traffic on the frequency. Of course, they also caution that before making any transmission the user is supposed to turn off the 'Private Line' to check to see if anyone else is already using that frequency. (In accordance with Federal Law.) Motorola did refer to the tone system as "Private Line", or just "PL" systems. Many of the older equipment had a toggle switch on the control head for this that was labeled PL, or Private Line, and all such radios were called "Private Line Radio". "CTCSS" was the abbreviation Motorola used for their 'Private Line' radios for ordering. They didn't mean that for use to ID the feature. Instead, they (since they were the only one to have it at the time) actually intended the feature to be called 'private line' radios, and that the abbreviation merely described what it did.
Dave DJnRF From: Dennis Smith m1dlguk@gmail.com To: Discussion of CHIRP chirp_users@intrepid.danplanet.com Sent: Tuesday, April 21, 2015 4:20 PM Subject: Re: [chirp_users] UV-82 "Privacy coding (tones)"
Jim, I'm sure you will agree with me that the marketing department in Motorola (who (if I'm not mistaken) first called them "Privacy Tones") must have known that they were blatantly misleading people, where as most other companies call them by the anachronism CTCSS correctly. This explains CTCSS for the lay-user quite well. https://www.youtube.com/watch?v=Zht-Y_QsZ2I
Dennis Smith M1DLG