L1708 is the databus used in most US citybuses.
The full name is SAE-J1708.
You use 485 transcievers and tie data out to Vcc and connect TxD to output enable. A resistor network keep the bus at a state when no Transmit enables are active. The output has 47 ohms between the transciever outputs and the bus, thus no overload with collision.

Erik