I spoke to the Russian guy who is involved with the Sun SDR Pro2 radio regarding how I can connect it to my SPE 1K amplifier and make sure that the amplifier follows the frequency and band changes. He was very helpful and sent me the following information. Unfortunately, I am not technically minded when it comes to stuff like this so it really doesn't mean much to me at all. I'm assuming I'm going to have to have some kind of cable constructed, rather like the one that I use at the moment between the radio and the amplifier for my 7800. However, could somebody explain in layman's terms what the following information actually means what I need to do. the PTT is on the pin8 of EXT CTRL connector and the ALC has a dedicated RCA socket. Regarding the CAT control, you have to create a COM port inside the PC software and set the amplifier to use CAT Kenwood at appropriate baudrate. The schematic of the CAT cord is the same of the Kenwood transceivers, page 31 of 1K-FA user manual.