2
CONTROL DATA TRANSMISSION VIA RS-422 BETWEEN THE MASTER
DEVICE AND THE SLAVE DEVICES
1. GENERAL
The universal rules of control data transmission for the Devices equipped with RS-
422 are defined by this protocol.
One or several slave Devices can be connected to the interface bus at any moment.
Only the Master may initiate transmission via the bus. The Master may be either a
remote PC or a control keyboard.
Control data are transmitted by byte blocks (1 byte is composed of 8 data bits) at the
rate of 115200 bps without parity control in the half duplex mode.
Once a Slave receives a control block addressed to it, this Slave must transmit a
response block no later than 500ms. Master must not begin a transmission of a new
control block without the reception of a response block to the previous control block
within the aforementioned time-out.
