TM-271A and a KPC3+

[KL7YK]

Ok, been trying to get these two to talk to each other using the internal packet connections.

The TM-271E has a mini-din connector on it for Packet, the A version (US Version) does not, but the connection points are still available on the board.

This mod has been addressed to a degree on the TAPR forums but not exactly fully described. (described by KQ4KX) Not complaining about that article I just am missing something from it.

So, with that here is my problem.

On the 271A I have the following connection points to the cable for the KCP3+:

Kenwood PKD Point is connected to KPC Pin 1
PKS point to pin 3
PR9 point to pin 5
GND to pin 9

Thats how the described connections are explained as far as I can tell. Radio is internal menu set to 1200 baud and the XMITLVL is set to 75 as outlined in the article I read.

This is not working nor is about any combo that remotely looks right. Recieve is fine, TNC show open squelch all the time. But no xmit until I turn the radio off (as in the TNC does not hear a busy freq).
If I reverse Pins 1 and 5 the TNC will send the transmit command but the radio basically resets (flashes on and on kind of thing, that can't be good!)
Tried that because have been bitten by the reverse veiw
effect on packet setups before.
So what am I missing here? If you have accomplished this mod please let me know what is to connect to what etc...

Ron, KL7YK
Anchorage

[KI4OIU]

Ron, I use the TM-271a and a kantronics KPC3 in my home APRS station...it works great.

I did the mod as described here:

http://www.kb2ljj.com/data/kenwood/TM-271A-E.htm

AND followed this bit of advice from the Yahoo Group for the tm-271a: ( YOU REALLY NEED TO HIT THIS GROUP!)

BEGIN COPY  
JC,
Just make sure your TNC is set to Carrier Detect CD Software. Running open squelch and not CD software, you will NOT transmit.
 
I've modified several of these radios.
 DB9 pins are : Pin 1 PKD, Pin 3 PKS, Pin 5 PR9 (I was using PR1), Pin 5 GRN.
I make a direct connection to the board with a BD9 pigtail. I don't use a pigtail with a mini plug and then make up a mating mini to DB9 to the radio. Cleaner connection if you know which TNC the radio will be connected.
 
73 Bill, W1GTT

END COPY

This allows me to use the radio with the hand mike as needed - and the aprs connection is permanent with no worries about squelch or audio settings, and NO NOISE!

JC - KI4OIU