[arm-allstar] CTCSS detect ping-pong - stumped

[Robert Conklin]

Greetings all. I'm stumped on a ping-pong PTT issue when using ctcss detect
output from my repeater's receiver.

Here's the layout:
Hamvoip 1.5 code, fresh image w/latest updates.
DMK URI
Motorola MTR2000 repeater in base mode. Programmed for PL on input and
output.
The MTR's CTCSS and COS detect outputs are active high (5vdc), I use a 10k
resistor to pull them low when inactive.
When using CTCSSFROM in usb mode, the CTCSS signal pin-pongs in fairly (not
perfectly) regular intervals, at about 1Hz, thus the PTT ping-pongs with
it. If I use COS, no ping pong. Transmission coming from telemetry or from
links are unaffected so it appears to be a repeater issue.
I scoped the COR and CTCSS signals and they appear completely identical in
amplitude, accept the CTCSS signal drops in and out BUT it only does that
when it's hooked up to the URI. That's the kicker, that CTCSS signal is
solid as a rock when I take it of the URI. I tried another URI with the
same result. I cannot see anything in the RSS programming for the MTR that
would change that CTCSS pin's behavior.
Would be very appreciative of any thoughts or ideas, thank you!

--
Robert Conklin
*N4WGY <http://qrz.com/db/N4WGY>*