[Motorola] Professional Radio CPS - A Caveat

[Eric Lemmon]

While programming a new HT-1250, I learned an important lesson re Pro
radio CPS.  Starting with CPS version R06.02.03 (HVN9025J), a number of
new features are now available- along with several bug fixes.  Among the
new features is the capability to encode and decode the CTCSS Reverse
Burst in either of the two formats defined in EIA/TIA-603, the industry
standard for two-way radio.

On the Advanced tab of the Conventional Personality menu, there is now a
box labeled "Non-Standard Reverse Burst."  If this box is unchecked- its
default condition- the CTCSS reverse burst is processed in the native
Motorola format, which is a 120 degree phase shift for 180
milliseconds.  If the box is checked, the reverse burst is processed in
the format used by Kenwood, Vertex, Icom, Johnson, Ericsson, etc., which
is a phase shift of 180 degrees for 150 milliseconds.  Late-model radios
use digital signal processing to encode and decode the CTCSS tones, and
it is easy to accept one format of reverse burst and reject the other. 
And that is why a Motorola radio both causes and suffers squelch crashes
when communicating with a non-Motorola radio, and vice-versa.

About that caveat:  When I programmed my HT-1250 to operate on both the
city (Kenwood) and county (Motorola) repeaters, I found that the
"non-standard" reverse burst was not working with the Kenwood repeater. 
After double-checking everything and coming up with no clue, I
discovered that my new radio was delivered with firmware revision
R05.00.03, while the other HT-750 and HT-1250 radios (which DID work
properly) had firmware R05.03.00 or R05.03.02 installed.  Aha!

I did some research, and I found that Motorola has issued a
Firmware/Codeplug Upgrade Kit to fix this problem.  Its primary purpose
is to upgrade the firmware to R05.03.00 so that the new CPS features
will be enabled.  Curiously, no mention was made in the CPS Readme file
that there was a firmware compatibility issue.  Once I flashed the
firmware to R05.03.00, everything worked perfectly.  EOS.

73, Eric Lemmon WB6FLY