Grass Valley RSAT1 - Manual (Page 33)

Satellite Panel RSAT1 6. Annex
28 Operating Instructions - Rev. 3 / 7.2002
6.4 COMMUNICATION GUIDELINES
Each side can initiate the communication by sending ‘?’ datagrams every two or
so seconds. When receiving ‘?’ the receiver ackknowledges with an Y datagram.
Each datagram – except Y,N,E – has to be acked within 30 milliseconds. Otherwise
it is re-transmitted after 0.5 seconds. After 5 consecutive re-transmissions it is as-
sumed that the partner has been powered off. This should be indicated somehow
and the communication state goes to sending ‘?’. The communication breakdown
indication can be one of the following:
D
undersurface LED with an appropriate symbol like on the DD35 control panel
D
running light over all buttons (like CP-3xx series panels when not polled)
D
lighting all buttons.
Status Diagram
IDLE
CONNECT
send ’?’
Process main loop
5 consecutive timeouts
Power-on
Valid command received