MagTek MCP - Manual (Page 34)

MCP Serial Transport Protocol
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Rule 2.3
A node that sends a BAUD_SYNC request shall continue sending BAUD_SYNC requests until
(a) it receives a valid response or (b) 2.5 seconds expire, whichever occurs first. The requests
shall be sent 75-125 milliseconds apart.
Establishing and Resetting a Connection
Rule 3.1
Nodes shall establish connection prior to exchanging user data. Only one connection may exist
between any two nodes.
Rule 3.2
A node can initiate a connection by sending a RESYNC S-frame request in compliance with
Rule 1.1. The node shall reset its send and receive sequence numbers prior to sending the
request. It shall ignore any incoming I-frames and R-frames until it receives a valid RESYNC S-
frame response with result code “success”. The node can retry the RESYNC request according to
Rule 1.3 .
Rule 3.3
A node that receives a RESYNC request may accept the connection by sending RESYNC
response with result code “success”. The node shall reset its send and receive sequence numbers
prior to sending the response.
Rule 3.4
Once a connection is established the nodes can exchange user data in both directions, regardless
of which node initiated the connection.
Rule 3.5
There is no direct way to dissolve a connection. If a node fails to send user data according to the
data transfer and error recovery rules below, it shall assume the connection dissolved.
Rule 3.6
A node can initiate resetting the connection by sending RESYNC request according to Rule 3.2.
Any outstanding unconfirmed I-frames shall be considered not transmitted successfully before
the RESYNC request is sent.