dspurg7310
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I don't really ever post things. I chose this specific area of the forum to post this due to a thread back in 2020 in this exact area where a couple people were requesting the exact information I include in this post.
This is purely an informational post to hopefully help someone else who may have a Trident Comm-TAC or Comm-TAC2 radio interoperability box.
The Trident company that made these is long since gone and no helpful documentation for these units exists anywhere on the internet (that I could find). A couple people in this very forum were looking for pinouts back in 2020. That thread has since closed and does not allow anymore responses. At any rate, I had to remove both a Comm-TAC and Comm-TAC2 unit from a mobile communications vehicle for a 9-1-1 dispatch center, and had the opportunity to "reverse-engineer" the pinouts with various different radios to confirm the working pinouts. They are as follows:
Comm-TAC (DB9 Connections):
Comm-TAC2 (RJ45 Connections):
These pinouts have been tested successfully with a couple Motorola (XTL 2500 & XPR 5550) and Kenwood (TK-8180) radios.
*Note on Kenwood TK series radios, Pin 6 on the DB25 connector is the MIC IN and is not expecting the hot audio signal that will come from the Comm-TAC. It is necessary to add a 15k-22k resistor and 1uF capacitor to this circuit to bring down the audio going into the Kenwood, otherwise it will be over-modulated and sound distorted.
*For the Comm-TAC with DB9, please note, that if your radio COR/COS is only active LOW and cannot be changed to active high, you will need to insert a transistor (PN222A - Leg 1 GND DB9's Pin 5, Leg 2 +V from radio, Leg 3 COR DB9's Pin 3 & tie in one leg of the 2.2K resistor to DB9's Pin 3 also, and the other leg of the resistor to radio COR pin). This had to be done for older Motorola XTL 2500 radios and they worked in this configuration for years on the communications truck.
I also have APX 1500, 4500, 6500 and 8500 mobiles, but have not had the opportunity to test those with these yet, but they use the same J2 accessory connector as the XTL 2500 and I assume are also active low for COR, so, same rules apply. The DB9 version expects active high, so if using with one of these radios, you will likely need to add the transistor and resistor to give it the active high signal it expects when detecting COR.
Hope this helps someone.
Have a good day, y'all.
(Images used for reference, publicly displayed, came from a bid listing on govdeals.com from 2019. I do not claim any copyright or ownership of the images.)
This is purely an informational post to hopefully help someone else who may have a Trident Comm-TAC or Comm-TAC2 radio interoperability box.
The Trident company that made these is long since gone and no helpful documentation for these units exists anywhere on the internet (that I could find). A couple people in this very forum were looking for pinouts back in 2020. That thread has since closed and does not allow anymore responses. At any rate, I had to remove both a Comm-TAC and Comm-TAC2 unit from a mobile communications vehicle for a 9-1-1 dispatch center, and had the opportunity to "reverse-engineer" the pinouts with various different radios to confirm the working pinouts. They are as follows:
Comm-TAC (DB9 Connections):
| DB9 PIN | FUNCTION |
| 1 | TX AUDIO (to radio) |
| 2 | RX AUDIO (from radio receiver) |
| 3 | COR/COS (active high) |
| 4 | PTT (active low) |
| 5 | GROUND |
| Pins 6-9 are not used here. |
Comm-TAC2 (RJ45 Connections):
| RJ45 PIN | FUNCTION |
| 1 | TX AUDIO (to radio) |
| 2 | GROUND |
| 3 | RX AUDIO (from radio receiver) |
| 4 | - |
| 5 | COR/COS (active low) |
| 6 | GROUND |
| 7 | PTT (active low) |
| 8 | - |
These pinouts have been tested successfully with a couple Motorola (XTL 2500 & XPR 5550) and Kenwood (TK-8180) radios.
*Note on Kenwood TK series radios, Pin 6 on the DB25 connector is the MIC IN and is not expecting the hot audio signal that will come from the Comm-TAC. It is necessary to add a 15k-22k resistor and 1uF capacitor to this circuit to bring down the audio going into the Kenwood, otherwise it will be over-modulated and sound distorted.
*For the Comm-TAC with DB9, please note, that if your radio COR/COS is only active LOW and cannot be changed to active high, you will need to insert a transistor (PN222A - Leg 1 GND DB9's Pin 5, Leg 2 +V from radio, Leg 3 COR DB9's Pin 3 & tie in one leg of the 2.2K resistor to DB9's Pin 3 also, and the other leg of the resistor to radio COR pin). This had to be done for older Motorola XTL 2500 radios and they worked in this configuration for years on the communications truck.
I also have APX 1500, 4500, 6500 and 8500 mobiles, but have not had the opportunity to test those with these yet, but they use the same J2 accessory connector as the XTL 2500 and I assume are also active low for COR, so, same rules apply. The DB9 version expects active high, so if using with one of these radios, you will likely need to add the transistor and resistor to give it the active high signal it expects when detecting COR.
Hope this helps someone.
Have a good day, y'all.
(Images used for reference, publicly displayed, came from a bid listing on govdeals.com from 2019. I do not claim any copyright or ownership of the images.)
