Comtech EF Data DT-4500-A Series - Manual (Page 115)

DT-4500-A Series Downconverters Revision 1
Appendix A MN-DT4500A
A–5
A.5.5 Response Timeout
A minimum of 500 milliseconds is provided before declaring a “no response” instance, at which
time the command is re-transmitted.
A.5.6 Bus Inactivity Requirement
Comtech EF Data recommends that a minimum of 50 milliseconds bus inactivity be provided by
the user between the receipt of a response from an addressed converter and issuing the next
command on the serial bus.
A.6 Message Structure
The structure of a Command, Response, or Error Message is as follows:
• Start Character
• Device Address
• Command or Response
• End of Message String
A.6.1 Start Character
The Start Character begins each message:
Example: < Start of a user Command.
> Start of a converter response.
A.6.2 Device Address
The Device Address consists of a Physical Address or a Physical Address and an appended Virtual
Address. This document uses DEV for the generic case examples.
Example: <3V12
A.6.3 Command
A Command is a variable length character string beginning with a forward slash “/”’ and
containing either an instruction or an instruction and data for a converter to act upon. If data is
passed by command it is appended to the instruction by an underscore “_”. If data is retrieved
by command, underscore follows the instruction, flagging the converter to supply data in a
response.