The Radio Information Board

Bingo, run the fcc id.

You cant scan channels in a system. You can only scan 1 channel per system. If you want to scan 8 channel then you need 8 systems with 1 channel each.

The 840 in convention mode is a nice radio but scan is rather strange. You get about 256 channels out of the radio in conventional mode. I foget the exact number. Its a mix of how many groups and how many channels in the groups. Each of the 32 groups can have upto 250 channels in convential mod. So ...

The kenwood programmer is just a level shifter. rs232 +-12v to ttl 5v.
Any of the max232 chips will do the work for you. If your rib has one then a cable to match tx and rx pins is about all you need.

You can program freq/pl from the front panel. Other features must be programmed from the computer port. The scan button may or may not be enabled. Buttons can be used for other functions as programmed from the comptuer.