Decoding P25 NSWGRN information
Posted: Fri Sep 03, 2010 4:58 pm
Scotty has asked me (in a PM) about how I decode the control channel info of our new P25 GRN, I hope you don't mind Scotty but I thought it would be easier to open up a discussion that everybody could join in on?
On the old 4.1 network (with a 3600 baud CC) it was a lot easier to decode the control channel data, just about any analog scanner with an easy-to-do mod (called a discriminator tap) was capable of feeding the info to a computer through the soundcard so it could be decoded with software (which I'll get to in a minute). However, with the upgrade to P25 (and more importantly to this discussion, a 9600 baud CC), a computer's sound card just doesn't have the audio quality necessary to pass three times as much data to the software. In other words, you will have very little success with P25 trunk sites unless you have one of the newer scanners with control channel data output (also known as CC Dump)?
I must also mention the FSK interface (or "data slicer") which takes audio from a scanner's discriminator tap and converts it to serial data, which when connected to the computer's COM port is another way of supplying the data to the software; however, others might have had more luck with this but I still couldn't get a slicer to work on a P25 CC? Even with a very strong signal I was getting a very poor decode rate... less than 5% which is pretty much useless!
So, which scanners have CC Dump? As far as I know the following list:
Dick Smith Electronics DTS96
Radioshack PRO96
Radioshack PRO106
Radioshack PRO197
Radioshack PRO2096
GRE PSR500 (and PSR500C)
GRE PSR600 (and PSR600C)
Uniden BCD396XT
Uniden BCD996XT
(and according to the PRO96COM website) Anritsu S412D Monitor (whatever that is?)
There are a couple of others with the CC Dump feature (the Uniden BCT15X for example) which are analog only scanners so I haven't bothered to mention them here.
It is worth noting that some of the above scanners will also display the radio ID (known in some of the brands as UID or Unit ID) as well as the talkgroup ID on the scanner itself without the use of any software, and I know the Unidens at least will allow you to alpha tag RIDs in much the same way as TGIDs, so a unit's callsign (or name) will appear on the screen in place of it's number.
Now to the software... there are a couple of popular choices for decoding software, there's a program called "PRO96COM" (available from this website) and then there's one called "UniTrunker" (available from this website). PRO96COM is probably the more "user friendly" of the two but I prefer UniTrunker myself, mainly for it's ability to decode and display multiple sites simultaneously and all using the same database (i.e. tag a RID on one screen and it's instantly tagged across all sites being monitored on the same system).
Both essentially do the same job so have a look at them and decide for yourself? BTW, both of the above software packages are FREE (who says nothing good is ever free these days)! There are some other programs around, such as "ID Trunker III", but the two above I would say are the most popular.
I think that about covers it, if I've overlooked anything I'm sure somebody else will chime in... Have fun!
Andrew
EDIT: Correcting a scanner model, thanks to Sigint for spotting it
On the old 4.1 network (with a 3600 baud CC) it was a lot easier to decode the control channel data, just about any analog scanner with an easy-to-do mod (called a discriminator tap) was capable of feeding the info to a computer through the soundcard so it could be decoded with software (which I'll get to in a minute). However, with the upgrade to P25 (and more importantly to this discussion, a 9600 baud CC), a computer's sound card just doesn't have the audio quality necessary to pass three times as much data to the software. In other words, you will have very little success with P25 trunk sites unless you have one of the newer scanners with control channel data output (also known as CC Dump)?
I must also mention the FSK interface (or "data slicer") which takes audio from a scanner's discriminator tap and converts it to serial data, which when connected to the computer's COM port is another way of supplying the data to the software; however, others might have had more luck with this but I still couldn't get a slicer to work on a P25 CC? Even with a very strong signal I was getting a very poor decode rate... less than 5% which is pretty much useless!
So, which scanners have CC Dump? As far as I know the following list:
Dick Smith Electronics DTS96
Radioshack PRO96
Radioshack PRO106
Radioshack PRO197
Radioshack PRO2096
GRE PSR500 (and PSR500C)
GRE PSR600 (and PSR600C)
Uniden BCD396XT
Uniden BCD996XT
(and according to the PRO96COM website) Anritsu S412D Monitor (whatever that is?)
There are a couple of others with the CC Dump feature (the Uniden BCT15X for example) which are analog only scanners so I haven't bothered to mention them here.
It is worth noting that some of the above scanners will also display the radio ID (known in some of the brands as UID or Unit ID) as well as the talkgroup ID on the scanner itself without the use of any software, and I know the Unidens at least will allow you to alpha tag RIDs in much the same way as TGIDs, so a unit's callsign (or name) will appear on the screen in place of it's number.
Now to the software... there are a couple of popular choices for decoding software, there's a program called "PRO96COM" (available from this website) and then there's one called "UniTrunker" (available from this website). PRO96COM is probably the more "user friendly" of the two but I prefer UniTrunker myself, mainly for it's ability to decode and display multiple sites simultaneously and all using the same database (i.e. tag a RID on one screen and it's instantly tagged across all sites being monitored on the same system).
Both essentially do the same job so have a look at them and decide for yourself? BTW, both of the above software packages are FREE (who says nothing good is ever free these days)! There are some other programs around, such as "ID Trunker III", but the two above I would say are the most popular.
I think that about covers it, if I've overlooked anything I'm sure somebody else will chime in... Have fun!
Andrew
EDIT: Correcting a scanner model, thanks to Sigint for spotting it