Using HDLC/LAP-D Protocol

Request Specific Processing

Control Requests

All control writes to this protocol share a common format. The first four bytes are defined as a header:

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Control Code

 

 

 

 

 

Control Length

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Packet Length

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Control Code Defines the action to be taken by this request.

Control Length The length of the data for this control request. This data immediately follows the header.

Packet Length Some protocols allow packet data (data to be transmitted over the wire) to be passed to a control write following the control request data. For this protocol, these two bytes must be zero because the protocol does not allow packet data within a control write.

This protocol allows the following Control Codes:

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CW_STATS

Send ST25L2STAT status message

This control write triggers the protocol to send a ST25L2STAT status message. For the format of this message, see the section on “Status and Error Messages”. Control length must be zero.

6CW_REVCODE Send ST25REVCD status message

This control write triggers the protocol to send a ST25REVCD status message. For the format of this message, see the section on “Status and Error Messages”. Control length must be zero.

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Chapter 3

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HP Advanced Communications Controllers (ACC) manual Control Requests