Comtech EF Data CDM-710, Инструкция по установке и эксплуатации

Страница: 177 / 242

CDM-710 Broadcast Satellite Modem Revision 11
Appendix A MN/CDM710.IOM
A–3
A.5 Packet Structure
Controller-to-Target
Start of Packet Target Address Address Delimiter Instruction Code Code Qualifier Optional Arguments End of Packet
<
ASCII code 60
(1 character) (4 characters)
/
ASCII code 47
(1 character) (3 characters)
= or ?
ASCII codes 61 or
63
(1 character) (n characters)
Carriage Return
ASCII code 13
(1 character)
Example: <0135/TFQ=0070.2345{CR}
Target-to-Controller
Start of Packet Target Address Address Delimiter Instruction Code Code Qualifier Optional Arguments End of Packet
>
ASCII code 62
(1 character) (4 characters)
/
ASCII code 47
(1 character) (3 characters)
=, ?, !, or *
ASCII codes
61, 63, 33, or 42
(1 character)
(From 0 to n
characters)
Carriage Return,
Line Feed
ASCII codes 13,10
(2 characters)
Example: >0654/RSW=32{CR}{LF}
A.5.1 Start of Packet
Controller-to-Target: This is the character ‘<’ (ASCII code 60).
Target-to-Controller: This is the character ‘>’ (ASCII code 62).
Because this is used to provide a reliable indication of the start of packet, these two characters may not appear anywhere else within the
body of the message.
A.5.2 Target Address
Up to 9999 devices can be uniquely addressed. In EIA-232 applications this value is set to 0. In EIA-485 applications, the permissible
range of values is 1 to 9999. It is programmed into a Target unit using the front panel keypad.
IMPORTANT
The Controller sends a packet with the address of a Target – the destination of the packet. When the Target responds,
the address used is the same address, to indicate to the Controller the source of the packet. The Controller does not
have its own address.