LTR-Net Data Description
From The RadioReference Wiki
LTR-Net Field Values
Channel In Use (CHiU) Field
1 - 20 Standard LTR LCNs 17 Radio Unique ID (when Home = 24) 18 Site ID (when Home = 24) 24 Channel Transmit Frequency 25 Channel Receive Frequency 26 Neighbor Site ID 28 LCN Channel Map
Home Repeater Field
1 - 20 Standard LTR LCNs 24 Special - see CHiU 29 Directed Group Call 30 Hang Code, channel is in use, but mute audio 31 Turn Off (Call/Command end)
Free Channel Field
00 No Free Channels Available 1 - 20 Standard LTR LCNs 21 Standard LTR Group Call 31 LTR-Net Group Call
LTR-Net Special Call Talk Groups (240-255)
x-xx-240 - x-xx-247 = Token Group ID calls. This is a temporary (token) group identifier that is assigned to the mobile for the duration of the call, when the mobile is making certain types of calls, like Auxiliary call, TELCO call, or Data call: x-xx-240 = Auxiliary Call x-xx-241 = Telephone to Mobile/Mobile to Telephone Call x-xx-242 x-xx-243 x-xx-244 x-xx-245 x-xx-246 x-xx-247 x-xx-248 x-xx-249 x-xx-250 x-xx-251 x-xx-252 x-xx-253 = Radio register - assign Unique ID/DONUT (Do Nothing) Call Group - used when the system is sending LTR-Net messages to a mobile and wants the channel to stay open, but doesn't want any of the mobiles to unsquelch their audio. x-xx-254 = CWID Morse Code FCC Callsign Broadcast x-xx-255 = Channel Idle
LTR-Net Radio Unique Identifiers
LTR assigns all radios to a group and when you call one radio, all radios in the group participate. LTR-Net allows calling to single radios by using the unique identifier assigned to each LTR-Net radio. Unique radio identifier messages can normally be found on traffic channels, because that's where the radio will be listening. Since mobile radios are not normally assigned to the Home Status Channel, you may not encounter any unique IDs there. The following is a LTR unique radio address message:
+ OSW: 0 17 24 003 10 1D (Unique ID 106)
The last three bits of the 24 field combine with the bits from 003 and 10 fields to form a 16-bit value that is the radio unique identifier. This addressing message is normally preceded and followed with a group 253 start message and a group 253 end (31-253) message.