M1225 PL/DPL Strip?

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cracked
Posts: 142
Joined: Thu Oct 11, 2001 4:00 pm

M1225 PL/DPL Strip?

Post by cracked »

According to the online help in the M1225 RSS , I'm supposed to be able to program an accessory connector input pin for "PL/DPL Strip" operation, but I don't actually see this option. What's the deal?
Al
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Joined: Tue Sep 04, 2001 4:00 pm

Post by Al »

If I'm remembering correctly, the PL/DPL strip option is only available if you're using an R1225 as a base/repeater station. That
option isn't available with the M1225 mobiles and [obviously] the
P1225 portables, all of which are programmed with the same RSS.
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cracked
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Post by cracked »

Al wrote:If I'm remembering correctly, the PL/DPL strip option is only available if you're using an R1225 as a base/repeater station. That
option isn't available with the M1225 mobiles and [obviously] the
P1225 portables, all of which are programmed with the same RSS.
That's what I was afraid of. Unfortunately, I happen to be using an M1225 as an exciter in a repeater and would like to strip PL when COS drops. My controller already introduces a PTT delay after the COS drops, but not all user radios support reverse-burst, so they get a squelch "tail" noise.

Perhaps this could be accomplished with a hard-wired connection into the radio some place (anybody?)...
Al
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Joined: Tue Sep 04, 2001 4:00 pm

Post by Al »

The CM200 & CM300 have accessory pins that can be programmed for PL/DPL strip......however, with the CM series, the strip pin must be in the active state before PTT goes active. If strip goes active while PTT is active, it doesn't strip PL/DPL.
In the M1225, PL/DPL baseband modulates the tx synthesizer's reference oscillator while the voice band stuff modulates the tx VCO directly. That method is standard with most if not all M products. I don't have a schematic in front of me, but if you could locate a convenient point where subaudible signalling baseband is injected into the tx reference osc and use a simple FET transistor switch to allow or disallow injection, that would do what you want.
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