Mark, Yes, they do. Just search for "telecommunications industry association." Here's the link for TIA-603-B:
<http://www.tiaonline.org/standards/search_results2.cfm?document_no=TIA-603-B> 73, Eric Lemmon WB6FLY Mark Holman wrote: > > Say Eric; > > In regards to Telecommunications Industry Association do they have a web > site ? > > Thanks > > MH > ----- Original Message ----- > From: "Eric Lemmon" <[EMAIL PROTECTED]> > To: <Repeater-Builder@yahoogroups.com> > Sent: Thursday, September 09, 2004 9:14 PM > Subject: [Repeater-Builder] CTCSS Decoder Response Times - General > Information > > > Several recent postings have mentioned that the speed of response to a > > carrier with a CTCSS ("PL") tone is faster with higher tones. It > > happens that there is an international standard, TIA-603-B-2002, which > > describes this and many other facets of commercial radio systems. The > > Telecommunications Industry Association standard is entitled, "Land > > Mobile FM or PM Communications Equipment, Measurement and Performance > > Standards." The great majority of reputable radio manufacturers certify > > that their products meet this standard. > > > > Paragraph 3.4.2.2 states that "The maximum attack time for CTCSS > > modulation shall be 250 ms except for frequencies below 100 Hz. Below > > 100 Hz, the time shall be computed by the following formula:" The > > formula is 25,000 divided by the CTCSS frequency in Hz; the answer is in > > milliseconds (ms). Given a low-end CTCSS tone of 67.0 Hz, a radio must > > respond within 373 ms. That's a long time! However, as several posters > > have noted, careful filtering of low-frequency noise and/or elimination > > of DC offsets can significantly reduce the response time. > > > > The same standard also specifies that CDCSS ("DPL") codes must be > > decoded within 350 ms. System operators who are considering using > > digital codes should be aware of this longer decode time. > > > > 73, Eric Lemmon WB6FLY > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
