Ingenico Developer Guide 2.03.024-028
Ingenico Download Configuration and Troubleshooting Guide 2.03.024-028
Telium Developer Guide 2.02.021
Verifone Developer Guide 2.19
Verifone Download Configuration and Troubleshooting Guide 2.19
Verifone Guides 2.18
Implementing TLS 1.2 to Simplify
Appendix C - Sample Link Level Exchanges (Serial Communications and USB emulating Serial)
POS device will attempt to transmit a message a parameterized number of times before assuming communications are lost.
Normally the POS and Simplify respond to each message received with an ACK. If a corrupted message is received, the response is a NAK.