diff --git a/v0.3/APCO25_V0.3.0.md b/v0.3/APCO25_V0.3.0.md index 21b1378..473d864 100644 --- a/v0.3/APCO25_V0.3.0.md +++ b/v0.3/APCO25_V0.3.0.md @@ -10,26 +10,25 @@ Decodes FDMA Common Air Interface (CAI) C4FM modulation and Linear Simulcast Modulation (LSM). ## P-25 Phase II -Phase II TDMA decoding is not currently supported. +Phase II TDMA (2 timeslot) traffic channel decoding. -## P-25 Hybrid (Phase I/II) -P25 hybrid systems use both Phase 1 control channels and Phase I and Phase II +## P-25 Phase I/II +P25 Phase II systems use both a Phase 1 control channel and Phase I and Phase II traffic channels, providing transition support for users with a combination of Phase I and Phase II radios. -TDMA configuration messages that are broadcast on Phase I control channels are -decoded. Currently these include the TDMA timing synchronization and TDMA -channel identifier messages. - ## Audio Vocoders ### IMBE ### -APCO-25 Phase I audio calls use the multi-band excitation model vocoder to -compress the digitized audio. SDRTrunk supports the JMBE library for decoding +APCO-25 Phase I audio calls use the IMBE vocoder for digital audio. + +### AMBE ### +APCO-25 Phase II audio calls use the AMBE vocoder for digital audio. + +SDRTrunk supports the JMBE library for decoding both IMBE and AMBE digital audio, but DOES NOT include the jmbe library in the normal application download. -You must download and compile the library and place the jmbe-x.x.x.jar file in -the same directory from where you launch the sdrtrunk application. On startup, -sdrtrunk will attempt to discover the library and can then decode imbe audio. +You must download and compile the library and use the **View >> Preferences** menu +to specify the location of the compiled JMBE library (jmbe-x.x.x.jar). [JMBE library](https://github.com/DSheirer/jmbe) @@ -46,9 +45,11 @@ decoder configuration when setting up the channel for decoding. ## Talkgroups and Addresses ## -All talkgroups and radio addresses are listed in hexadecimal (base-16) notation -and use the digits 0 - 9 and the letters A - F. Talkgroups are four characters -in length and radio addresses are six characters in length. +All talkgroups and radio addresses are presented in decimal or hexadecimal +(base-16) notation (see Preferences). + +### **Talkgroups**: 1 - 65,535 +### **Individual Radio Identifiers**: 65,636 - 16,777,211 Packet data IP Version 4 addresses will normally show in the from column of the events window and the Logical Link ID (radio address) will show in the from @@ -61,18 +62,17 @@ will be appended to the IP address. You can create an Alias List and attach it to your P25 decoder in the channel configuration window. -When aliasing talkgroups and radio addresses, ensure you include the full 4 or 6 -character talkgroup or address with leading zeros. +When aliasing talkgroups and radio addresses, you can use either a single talkgroup decimal value, or you can enter a range of talkgroup decimal values. -Add these trunking system unit ID values to your alias list: +Optionally, add these trunking system unit ID values to your alias list: -**FFFFFD** = (Trunking) System Controller. -**FFFFFE** = Registration Controller -**FFFFFF** = All Call +16,777,212 = (Trunking) System Controller. +16,777,213 = Registration Controller +16,777,215 = All Call ## Modulation ## -Choose either C4FM or LSM Simulcast (CQPSK) modulation in the channel configuration +Choose either C4FM or LSM Simulcast (CQPSK) modulation for Phase 1 channels in the channel configuration decoder tab. When you select the P25 Decoder from the drop-down list, the modulation selector list will appear. @@ -88,7 +88,12 @@ traffic channel frequencies used by the system because the control channel will tell the sdrtrunk application every thing that it needs to know in order to setup a temporary decoding channel. -### Traffic Channel Pool ### +**Note**: Phase 2 capable trunked systems will use a Phase 1 control channel +with Phase 2 traffic channels. You only have to setup one channel configuation +for the Phase 1 control channel. The Phase 2 traffic channels will be +automatically created by sdrtrunk as each call occurs. + +### Traffic Channel Pool Size ### When configuring the P25 control channel decode configuration, use the Traffic Channel Pool setting to set the maximum number of temporary traffic channels @@ -97,10 +102,13 @@ channel configurations up to this maximum number and reuse the channel configurations for subsequent calls. The default value of 4 traffic channels in the pool is suitable for a modern -powerful processor. You may have to reduce this pool size if you are using a -lower powered CPU. Monitor the computer's CPU and memory consumption and adjust -this value as needed. Note: you'll have to stop and restart the decoding after -you change the traffic channel pool size value and save it. +powerful processor. You can increase this value to match the number of traffic +channel frequencies for the system your are monitoring, provided your computer +is capable of running that many channels at the same time. You may have to reduce +this pool size if you are using a lower powered CPU. Monitor the computer's CPU +and memory consumption and adjust this value as needed. Note: you'll have to +stop and restart the decoding after you change the traffic channel pool size +value and save it. ## P25 Decoding Example ##