Star Micronics TCP300 Programmer's Manual page 5

Host
Command sent
NAK received
Command resent
ACK received
Response received
NAK sent
Response received
ACK sent
Host
Command sent
DLE received
See section 2-5. Transmission Control Characters for details regarding DLE transmissions,
ACK, NAK and DLE character codes.
Resend Sequence
DLE Sequence
3
Reader/writer
Command received
NAK sent
Command received
ACK sent
Command processed
Response sent
NAK received
Response resent
ACK received
Reader/writer
Command received
DLE sent