Bus(+) messaging protocol

skmcgee · Post by **skmcgee** » Mon Mar 11, 2002 7:55 am

I'm trying to figure out the messaging protocol used at the Bus(+) pin at the accessory connector located at the back of a CDM1250 radio. I have a little figured out, but have a long way to go. Any help or information would be appreciated. Thanks.

Nand · Post by **Nand** » Mon Mar 11, 2002 7:10 pm

skmcgee · Post by **skmcgee** » Tue Mar 12, 2002 6:22 am

Thanks for the reply. And I do have some figured out. For example, ramping up a channel (same as pressing the ^ arrow button) sends a message 0xF4 0x24 0x04 0x01 0x00 0xE2. I know the first byte lower nibble is message length (add 2). The 0x04 equates to that paricular button. The 0x01 is equivalent to a button press, and on the button release that changes to 0x00. Things like that. But there are still lots of things I'm guessing at.

Nand · Post by **Nand** » Tue Mar 12, 2002 2:51 pm

phantom · Post by **phantom** » Wed Mar 13, 2002 3:55 am

Welcome to the world of SB9600. I know of a company (can't remember the name) that actually uses the SB9600 protocol to perform all the functions of a radio (channel up, channel down, picking a channel, RSSI...) for something like MDT's or AVL's or the such. Sounds similar to what you're looking at...

Good luck!!!
PH