Generic Packet Structure - Kramer KDS-USB2 User Manual

Kramer Electronics Ltd.

2.1 Generic Packet Structure

All packets contain the following:
Magic Number
Message ID
Protocol Version
Command
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All multi-byte fields are packed as big endian.
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Messages are at least 10 bytes and at most 136 bytes in length.
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Any string fields should be encoded using UTF-8.
SwitchableUSB – 2
A value (0x2F03F4A2) which gives some confidence that the data
which follows is a configuration message.
When the client sends a request, it chooses any value to insert in
this field. The device responding to the request will set this field in
the reply to the same value it received in the request.
An integer from 0-255. All devices will support protocol 0 and one
other protocol version. The Reply Device Information message
will inform a client which version of the protocol it must speak in
order to communicate with the device.
An integer from 0-255. This is the identifier of the command. The
combination of the protocol version and the command identify a
unique message type. In other words, command 5 in protocol 1 is
likely different from command 5 in protocol 3.
General Information 4