LTR Protocol Details

[b52hbuff]

Where is a link to find out how the basic LTR protocol works?

I understand that LTR uses sub audible data to transmit trunking information and that there isn't any dedicated control channel.

I understand with Moto/EDACS trunking the radio sends a 'grant request' to the controller on the trunk channel to have the controller grant it one of the voice channels to use for the transmission...

How does an LTR radio send a grant request? If the radio's 'home repeater' is busy, then how does it know whick repeater to use? How is this information shared with the other radios? Does the assignment to the next open repeater happen as soon as a TGID's home repeater becomes busy?

...I'd like some more detail on the protocol so I could understand this... Thanks.

 

[WayneH]

Here's more info from a RR member's site: http://home.hvc.rr.com/bpetrow/ltr.htm If he doesn't provide enough click the link at the bottom for the PDF file hosted by Optoelectronics. THAT will get you covered.

The mobile sends a request via the input to the repeater. The LTR controller checks the group to see if it is in the database and able to complete a call. If it is it announces the call over the output. If there is another call in progress the home channel announces other channels as being available and idle. The radio looks for that channel ID in its programming and attempts to make a call in the same manner as earlier. Using a program like LTRDump/LTRTrunk you can see this when listening to an active LTR call.

The signaling is very basic.

-Wayne

 

[cg]

this is a patent for an improvement to LTR but has detailed description of the LTR protocol (maybe too detailed) the numbering references drawings.

http://patft.uspto.gov/netacgi/nph-Parser?Sect2=PTO1&Sect2=HITOFF&p=1&u=%2Fnetahtml%2Fsearch-bool.html&r=1&f=G&l=50&d=PALL&RefSrch=yes&Query=PN%2F5159701

chris