Communication
When power is first applied, the OSM-CPI will indicate that it is powering up by cycling its diagnostic
LED through the sequence: off, red, blue, green, and off (about about a half-second per color). The
diagnostic LED will then be solid white for about 2.5 seconds, then solid blue again for about a half-
second before polling begins.
After powering up, the OSM-CPI will first send an osdp_POLL command. It will continue to send
osdp_POLL commands at approximately 1.2 Hz until it receives an osdp_ACK reply. The OSM-CPI
will send an osdp_ID command, and will continue to do so at about 1.2 Hz until it receives an
osdp_PDID reply. After the first correct reply has been received, the OSM-CPI will send an
osdp_CAP command, expecting an osdp_PDCAP reply. If the OSM-CPI receives an incorrect reply
or a reply is never received, the unit will restart the connection sequence from the beginning.
At this point, to initiate a secure channel session with the attached PD the OSM-CPI sends the
osdp_CHLNG command, receiving and validating the osdp_CCRYPT reply from the PD, sending the
osdp_SCRYPT command, and finally receiving and validating the osdp_RMAC_I reply. If the reply to
any of these commands is incorrect or never received, the OSM-CPI will restart the connection
sequence from the beginning
After communication initialization, the OSM_CPI will begin sending the osdp_POLL command at
about 8 Hz until either the PD’s reply is not osdp_ACK, or one of the OSM-CPI’s digital inputs
change state.
If either of the OSM-CPI’s LED inputs change state, it will send an osdp_LED command with one of
four payloads depending on the states of the two LED inputs after the change. All configurations
send a permanent LED command to reader 0, LED 0, with the color of the LED set according to the
following table:
