According to documentation I read somewhere at one time, SB9600 is
> essentially half-duplex, so while the bus driver and bus reciever are
> "full duplex", it is for jabber and collision detection. I think it's
> documented in the Siren/PA amplifier manual, e.g. HLN1185.
I know it's covered in the Microcomputer section of the service manual.
Wouldn't surprise me if each peripheral device manual covered it too.
There's a busy line used for claiming the bus, and then the radio
monitors the transmitted data to make sure it receives what it sent, or
it retries.
De
