MagTek MCP - Manual (Page 33)

Section 4. Protocol
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RULES
Service Requests
Rule 1.1
A node can send a service request (S-frame request) at any time. The node shall not send another
service request until it receives the service response or the block wait timeout expires.
Rule 1.2
A node that receives an S-frame request shall respond with an S-frame response. If the node does
not recognize the command ID or any of the parameters, the response shall contain the “not
supported” result code.
Rule 1.3
All nodes shall recognize RESYNC and ECHO S-frame requests.
Rule 1.4
A node that sends an S-frame request and does not receive the corresponding response within the
block wait timeout shall either (a) resend the request according to Rule 1.1, or (b) give up.
Baud Synchronization
Rule 2.1
A node can send a BAUD_SYNC request at any time when S-frame requests are allowed
according to
Rule 1.1 . The baud synchronization request shall contain data that allows a
receiving node to determine the line communication parameters without ambiguity (for RS-232,
the data is “MT”)
Rule 2.2
A node that receives a BAUD_SYNC request without error shall respond with BAUD_SYNC
response with response code “success”.