Actually it was developed for the military in the 1940's if you do a search on Motorola and Fred Link gear for the military I think you will find the first lists of PL or CTCSS tones used-I use to have the references but have long since purged them from my system-PTT was invented in the 1930's, is anything really new?
From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Mike Morris WA6ILQ Sent: Thursday, September 17, 2009 6:09 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Anybody have some REALLY old Moto manuals? If so, I need a favor. The first implementation of PL used about 20 tones. The 32-tone "standard" list didn't come until later. Does anybody have a copy of that early tone list? It would have been somewhere in the 1950-1955 time frame. Thanks in advance. Mike WA6ILQ
