Whoever said that the two chips installed in the radio only send a TTL 
signal to the DIN jack was correct.

One of the chips is a Ne4040, the other, I think, is an 8281.

If you are looking for that chip set, you can confirm those numbers 
with numerous TS440 modification sites.

If someone is looking for them, I have a spare set of them somewhere, 
since I bought multiple sets from Jameco in the early 90's rather than 
buy one from Kenwood at double the price plus shipping.

To use the TS440 with a computer, you will also need the TTL to RS232 
interface from Kenwood that was mentioned earlier, or you will need to 
find an alternative circuit. I think I remember seeing one 
specifically for the 440 a long time ago in QST, but I may be 
mistaken.



Mike Duke, K5XU
American Council of Blind Radio Amateurs