Ok I got this a couple of years ago over at another web site that is down under when I first started to use tait radios. I had a tait TP9400 at the time and it did work for me on my county system here in maryland.
I do not know if this is still workable but with my portable it did work for me. It is kinda long and it might help if you have the tait software open to look at it while reading as well to help you better understand
Easiest way to use a TM9100 as a P25 scanner is as follows:
1: Go to Menu>Channel Profile>Basic Settings- and create a profile for P25 with all the standard settings and name it to suit the system you wish to monitor i.e. "P25 NSW GRN". In Menu>P25 Common- enable "Talk Party ID Display" this will help later as we add ID aliases. In Menu>P25 Conventional- under "Basic P25 Settings" set Talkgroup Selection Type to Selectable, and for Rx Unmute Rule set it to Selective. You CAN use "Monitor" as the Unmute rule to hear everything, but in this instance we will be using a different method to achieve the same functionality to hear all, This will be explained shortly.
Make sure you click the "Late Entry Fast Unmute" checkbox, although if encryption is sometimes used on talkgroups that you would like to monitor, you might want to leave this unchecked to avoid short bursts of crypto noises.
-You will have to create a new channel profile for each different system.
2: Create a zone and program all the frequencies for the intended systems local tower/s as RX only, in P25 only mode (not Mixed mode), use RX NAC of F7E (This is the wildcard NAC - saves a few ms unmute delay time and part of the "Hear All" ability). Set Tx Power to OFF
3: Set RX channels as a single conventional scan group for a base setup. You can use voting scan for a mobile setup. Don't add ANY other channels to the scan group, except channels for the same system from a different site. I'm not saying you can't... but it essentially negates the functionality as a P25 scanner if you add analogue ch's or different P25 systems to the list. Keep 'em separate.... you could even consider using an entirely separate zone for the P25 ch's or use a zone per system basis.
- You CAN use different P25 systems in a single scan group, but the more you add, the less likely you are to catch full conversations. Use "In-Zone Scan Member" setting on the channel summary page, and set the group up in Menu>Channel Setup>Scan Groups. I usually leave the Control Channel out of the list to help the scanning function.
Ok, on to the nuts and bolts of the show..... Ill try to keep it detailed, but brief.
4: While in Scan Groups, in the Membership tab add the Ch's to the Group Membership and Label the Group accordingly. In the Common Options Tab set Group Type to Scan for Base setup or Vote for Mobile setups. Set both Group Hold Times to 0, and enable the "Allow Scan When Off Hook". Under the Scan Tab Set the scan type to Standard, do not set to Talkgroup the Talkgroup scan is for actual Trunking setups. Leave "Group Standby Time" as 0. Use "Validate signal while scanning" if you have the Control Channels in the scan list.
5: Go to Menu>P25 Digital>Talkgroup Lists Rename the first Talkgroup List as the name of the P25 System, i.e. "NSW GRN TGs" or... whatever system you intend to monitor. Make a new one for different systems and label accordingly... this will help later when adding systems.
6: Under "Talkgroup Members" make a new entry and use 65535 (FFFF Hex) as the group ID, Label it as "Open" or "All" or whatever you like. This is the wildcard for talkgroups, so F7E as the NAC, and 65535 as the Talkgroup viola the radio will open to all voice. This is the "Hear All" function. It's up to you to monitor the system/network and log all the Talkgroups down and add them in with respective aliases as you go along, or get on the Googleplex and look up some info from online databases and references to get a list of Talkgroup ID's for the system you intend to monitor. For the purpose of correct functionality you will need to add a MINIMUM of 2 Talkgroups - This is so the TG selection we set up later will work. With only one TG programmed in the software will not allow the use of a TG selection menu
7: Back in Menu>Channel Profiles>P25 Common- Set the Call list as Call List 1, it's just a dummy call list at the moment, as time goes on you can add Individual radio ID's here with an Alias to identify particular users. Set Talkgroup Set to the specific Talkgroup to match the profile and system i.e. the "NSW GRN TGs". Down the very bottom of the page you will see a drop bar that selects the profiles - dont over look that, you may be setting the wrong TG's to the wrong Profile.
8: Go to Menu>Function Ctrl Settings- Set scroll keys to Channels Menu, and set the Left selection key to Talkgroup Menu, then use a pair of keys from Key 1 - Key 5 as the Zone Increment/Zone Decrement.
That should get the Tm9100 pulling out some sweet, sweet P25 audio for you on a per talkgroup basis, with a Monitor function. But... before you run off and start fiddling, there's a few warnings to heed:
If you DO transmit on the network while using this setup, the core Zone controller will flag an alarm in UEM (Unified Event Manager) and the NOC will see it as an illegal signal and log the ID of the radio. From here they can add a Stun command in active mode which will brick your radio instantly, or passive mode that will brick your radio the second the Zone controller sees anything from your ID anytime in the future. Don't be stupid and try to drop carriers over the network, the only person that will hear you is the Zone controller and UEM (both are software on the core). They will log your RSSI, and the Site that heard your carrier, the Tech's and Engineers will do the rest.
Speaking of Zone Controller, P25 systems work on a functional resource management system. If you are trying to listen to the Ambulance TG, and there is no Ambulance radios affiliated with the network through the site you are monitoring, then the zone controller will not rebroadcast the TG through any channel on said site. Therefore, it is probably prudent to add a 2 or more sites for the same network to the scan group... if you are in a position to do so.
