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Comtech EF Data KST-12025 User Manual

Page 112

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Remote Control Operation

KST-12025 Ku-Band Satellite Terminal

A–2

Rev. 1

A.2 Message

Structure

The ASCII character format used requires 11 bits/character:

1 Start bits

7 Information bits

1 Parity bit (odd, even)

2 Stop bits

Messages on the remote link fall into the categories of commands and responses.
Commands are messages which are transmitted to the RFT-1225, while responses are
messages returned by the RFT-1225 in response to a command.

The general message structure is as follows:

Start Character

Device Address

Command/Response

End of Message Character

A.2.1 Start

Character

A single character precedes all messages transmitted on the remote link. This character
flags the start of a message. This character is:

“<” for commands

“>” for responses

A.2.2 Device

Address

The device address is the address of the controller which is designated to receive a
transmitted command, or which is responding to a command.

Valid device addresses are 1 to 3 characters long, and in the range of 1 to 255. Address 0 is
reserved as a global address which simultaneously addresses all devices on a given
communications link. Devices do not acknowledge global commands.

Each RFT-1225 which is connected to a common remote communications link must be
assigned its own unique address. Addresses are software selectable at the modem, and must
be in the range of 1 to 255.