SDP1/2

Forum to post information about the San Diego City Trunked Radio System. This is the best place to post newly discovered talkgroups and other info that pertain to this system.
SkipSanders
Posts: 168
Joined: Sun Dec 03, 2006 10:12 pm

Postby SkipSanders » Sat May 17, 2008 2:01 pm

The Phone Patch talkgroup/frequncies are for field units (normally sargents and above only would have access, I expect) to phone patch from a scene. What they'd use if they didn't have a personal cellphone available. Very rare use, given the availability on most any scene of multiple cellphones these days.

800
Posts: 113
Joined: Sun Oct 08, 2006 4:35 pm

Postby 800 » Sat May 17, 2008 2:55 pm

SkipSanders wrote:The Phone Patch talkgroup/frequncies are for field units (normally sargents and above only would have access, I expect) to phone patch from a scene. What they'd use if they didn't have a personal cellphone available. Very rare use, given the availability on most any scene of multiple cellphones these days.


OK. But the two Phone Patch channels are not the same as the two console - console system link circuits this thread is addressing.

Don

OSW
Posts: 33
Joined: Sat Oct 01, 2005 3:06 am

Postby OSW » Tue May 20, 2008 10:26 pm

I think the "phone" part of "phone patch" for 3056 and 3120 was an ignorant assumption from long ago. I believe the original purpose (long ago) for the TG's was for patching other elements in to the system.

I don't believe the new system has telephone interconnect since it requires specific interconnect equipment I doubt City would have found ground to budget for. When the old system did I was only aware of Radio Services having access to it and it was only who I heard.


I think some are still confused about what SDP1/2 are. They are a dedicated audio PATHS (think link) between the two systems to easily facilitate patching between them. Without it you need to connect a subscriber radio - with the other system programmed in to it - to the console infrastructure.

w6pix
Posts: 338
Joined: Wed Dec 31, 1969 4:00 pm

Postby w6pix » Tue May 20, 2008 11:55 pm

Just toss in my 2 cents here RE: the phone patch

ABLE birds have it. They go thru phases of using it, but they use it from time to time. I've heard them call the RP directly for first hand details.

It is on a trunked frequency, not a dedicated freq. I don't remember which it is, I lost it when I reset my Pro 2006, but it was a freq that did get trunked coms most of the time, except whenever a phone call had it locked.

From a person I know who uses the phone patch, you just get a delay if the freq is busy, then it gets locked for the call. It's always the same freq.. If I turn it up again, I'll post it.

However, this was all before the upgrade. I have no idea if anythings changed.

OSW
Posts: 33
Joined: Sat Oct 01, 2005 3:06 am

Postby OSW » Thu May 22, 2008 1:16 am

w6pix wrote:From a person I know who uses the phone patch, you just get a delay if the freq is busy, then it gets locked for the call. It's always the same freq.. If I turn it up again, I'll post it.
With Motorola trunking each frequency has additional equipment specifically for that channel to facilitate making a call, hence why there always seems to be a slim amount of freqs used for interconnect.

Those that monitored the old Disneyland system will have seen the same thing. They recently upgraded the whole system and didn't include the hardware to support it.


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