[App_rpt-users] Addendum to Systel Repeater interface message

Bryan D. Boyle bdboyle at bdboyle.com
Wed Jun 12 22:21:29 EDT 2013

Well....digging into building a more robust (and at the suggestion of
Scott KB2EAR) or fault tolerant sense mechanism (ie it's better to be
active high for the COR in case the radio goes tango uniform or looses
power than active low to prevent dead keying)...so...

Dug into the Systel with a digital meter...(it was handy and didn't want
to go into the next room to get the 260; I usually like to see swinging
needles rather than flipping LCD numbers...), and hitting the points on
the receiver side of the board along the same connector as I was using
to pick up the CTCSS (active low signal on pin 5), found the pad next
(Pin 4) to it, marked on the schematic as, strangely enough, carrier
detect, which in testing was an active HIGH pin with a valid carrier.
Light bulb over the head time.  Duh, even I get it sometimes....

So...ran another lead from carrier detect on the Systel receiver
interface pin 4, moved the lead that was on the COR detect pin on the
URI as a pseudo-detect inverted signal from the COR detect on the radio
to its rightful place of pin 7 on the URI, new lead to pin 8...and in
usbradio.conf changed the carrier detect from usbinvert to usb,
ctcssdetect to usbinvert from no, restarted asterisk.

Nice.  Came right up.

I was joking with KB2EAR on Monday night that there doesn't really seem
to be any radios that you can't interface with the URI.  I've even
hooked up Wouxun HTs and gotten them to work (albeit with VOX...friends
don't let friends use VOX, but it was to prove a point).

Moral of the story: keep hacking at it.  You CAN get it to work.
Thinking it might be a problem on my TS830S, but you Never Know.

Oh, and in investigating the input to the transmit side...Systel injects
audio after what would normally have been the pre-emph circuit in the HT
audio stage.  So, added in some txpre-emph.  Sounds A Whole Lot Better.

Keep on burning rosin, folks.


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