How does patching work?

[gr8rcall]

Can someone provide me with a link that tells about the technical activity (it can be a complicated definition) that happens when 2 talkgroups are patched together on Motorola system(s). I'd like it if it would define what happens when 2 talk groups on DIFFERENT SYSTEMS are patched together.

Looked for one, but couldn't seem to find anything...

Also, whenever the dispatchers here patch a talkgroup from one system to a talkgroup on a another system, I can't get them to show in Unitrunker. Anyone know what's going on there?

 

[cabletech]

Basicly, patching between talk groups on one system to another, is done at the dispatch center.

A user on system A requests to be patched to a user on system B, the dispatcher has the ablity to 'toggle' to system B and this allows the two users to talk to each other.

When this happens, you will not see any information from user B.

This is not a normal function and is only used for incend interop.

 

[im800mhz]

It all really depends. You can merge talkgroups on the same system together. You can also patch a trunked to a conventional. You can also patch 2 trunked systems together via wireline, or control stations. You can even use ISSI to do it. It really all depends.

 

[KE4ZNR]

It all really depends. You can merge talkgroups on the same system together. You can also patch a trunked to a conventional. You can also patch 2 trunked systems together via wireline, or control stations. You can even use ISSI to do it. It really all depends.

Yep. Considering gr8calls location I am gonna assume he is
inquiring about VIPER and/or Guildford Counties trunked systems which
are Motorola.
gr8call: as im800mhz says above patches can happen in a number of different ways on a Motorola system. You can have regular patches between 2 talkgroups on the same system. You can patch 2 talkgroups from 2 different systems together. You can patch a Trunked talkgroup to a conventional channel. We do this with our FD VRS: One of our city OPs talkgroups can be patched to one of our 3 conventional VRS 800Mhz Freqs for use on fireground situations where needed.
There are many different types of patches.
Kind of difficult to give a quick explanation of every type of patch.
Marshall KE4ZNR

 

[n5ims]

The simplest patch is a radio on one system (or frequency) and another on the second system (or frequency) that are connected in a way so what's received on one is retransmitted on the other. The radios can be the standard ones used in a mobile or base, nothing fancy, and the controller is also nothing fancy it just takes whatever one is receiving a signal and keys the transmitter on the other (the speaker from one is connected to the mic input of the other).

There are fancier ways to do this using specialized system equipment that's designed to link systems together if the two radio solution can't handle what is desired (say the systems aren't close enough for good signals to both or multiple talkgorups/frequencies are desired).

During the Deepwater Horizon disaster in the gulf several systems were patched together in Florida, Alabama, Mississippi, Louisiana, Texas, and Illinois using the Motorola ISSI product. This allowed support teams throughout the area to communicate with themselves as well as experts and the various state and federal government agencies using common talkgroups and whatever system that had coverage in the area. This thread (http://forums.radioreference.com/te...assive-system-patch-gulf-oil-spill-works.html) has some of the details of this massive patched network.

 

[greenthumb]

Patches work differently when when it involves two trunked talk groups on one system vs. between two systems. When patching two talk groups on the same Motorola system, the first talk group selected by the dispatcher on a Centracom or MCC7500 console will be the patch 'supergroup'. Every talk group selected thereafter will be a member within the supergroup. Basically, this means that the system will broadcast messages on the control channel saying "hey radios, anytime that I say that the supergroup is being used, treat that the same as if you were receiving a call on any of the following talk groups too..." and lists those talk groups. It also tells the radios that if they place a talk group call on a supergroup member to expect the system to tell the radio that the channel grant is the supergroup instead.

ISSI excluded, patching across systems is typically accomplished via some kind of interface to a radio or other analog wireline interface. If no other talk groups are involved in the patch, the system just passes the audio between the two resources (conventional/BIM and trunking talk group) and the supergroup functionality is not used on the trunking system.

For ISSI, the proprietary patching functionality (Motorola or otherwise) does not pass across the ISSI link because neither end understands the proprietary patching methods, so a more inefficient patching functionality must be used, and this involves using two RF and/or ISSI talk path resources for the call. But the ISSI does support mapping a normal talk group call between the systems, and those mapped talk groups are statically configured in the ISSI gateway server.

 

[gr8rcall]

Yep. Considering gr8calls location I am gonna assume he is
inquiring about VIPER and/or Guildford Counties trunked systems which
are Motorola.
gr8call: as im800mhz says above patches can happen in a number of different ways on a Motorola system. You can have regular patches between 2 talkgroups on the same system. You can patch 2 talkgroups from 2 different systems together. You can patch a Trunked talkgroup to a conventional channel. We do this with our FD VRS: One of our city OPs talkgroups can be patched to one of our 3 conventional VRS 800Mhz Freqs for use on fireground situations where needed.
There are many different types of patches.
Kind of difficult to give a quick explanation of every type of patch.
Marshall KE4ZNR

That's exactly what I'm talking about. I'm not asking for a "Quick Explanation." ANY explanation, about ANY kind of patching will do. I've got plenty of time to read it. I would prefer one about patching different Talkgroups on different systems together.

Sorry if I wasn't specific enough....

Thanks,
Gr8rcall

 

[RKG]

Conventional patches are usually handled by a dispatch console.

1) Console operator selects a patch and populates it with Ch. A and Ch. B. (To keep things simple, assume both channels are repeated via this console.)

2) Subscriber keys up on Ch. A (which means he is transmitting on the Ch. A input frequency). One or more receivers unsquelches; comparator selects one. The audio from that receiver is passed up to the console Rx line and triggers the console Rx VOX function.

3A) Console does what it ordinarily would do on receipt of an inbound call on Ch. A. Passes recovered audio to the console operators. Also triggers an EIA keying sequence on the Ch. A Tx line, and passes same recovered audio down this line, which causes the transmitter to key up and pass that audio on the Ch. A output frequency.

3B) In addition, since the patch is up, console also sends an EIA keying sequence down the Ch. B Tx line, coupled with the recovered audio from Ch. A. Subscribers (other than the initiating subscriber) on both Ch. A and Ch. B hear the audio from the initiating subscriber on Ch. A.

4) Same sequence for replies, on either Ch. A or Ch. B.

5) If console operator presses master Xmit key, he transmits only on whichever channel is "selected." However, if he presses "Patch Xmit" key, he will transmit simultaneously on all of the patch member channels.

6 Note that a patch is not the same as a "Multi-Select" (Motorola) or "Simul-Select" (Zetron). When console operator has set up a multi-select, he will transmit on each of the multi-select member channels whenever he presses the master Xmit key. However, inbound traffic on any of these channels will not be retransmitted on the other channels.