OSDP-Legacy Controller Interface
Signals and Pinout
The OSM-CPI has a single 4 position terminal block, and a 10 wire flying lead interface. The signals of the terminal blocks and flying leads are named according to the diagram below.
Power can be supplied to the OSM-CPI by either the red and black flying leads, or pins 1 and 2 of the terminal block. These connections are common, and are intended to be used to pass power through the OSM-CPI from the flying leads to a peripheral device connected to the terminal blocks. Do not connect two sepatate power supplies to these connections. The OSM-CPI can operate using between 6 and 36 volts DC input, and draws at most 200 mA at 12 V.
The OSM-CPI uses the DS3695 RS-485 transceiver to interact with the RS-485 bus and to communicate with other OSDP compliant devices. The OSM-CPI supports communication speeds of 9600, 19200, 38400, 57600, and 115200 bits per second, and defaults to 9600 bps. The communication speed can be changed by issuing an osdp_COMSET command to the OSM-CPI in PD mode. The RS-485 B and A signals are connected to the terminal block pins 3 and 4, respectively.
The OSM-CPI’s Wiegand output D0 and D1 signals are connected to the green and white flying leads, respectively. The Wiegand outputs are open-collector NPN transistors, pulled up to 5 volts internally through diodes and 680Ω resistors. Wiegand transmissions are nominally 1000 bits per second, with a pulse-off time of about 100 µs. The OSM-1000 can handle between 1 and 255 bits of Wiegand, and handles special cases for 8 bit burst keypad readers.
Other Digital I/O
The OSM-CPI has two dedicated digital inputs, two signals that can be either inputs or outputs, depending on configuration, and two dedicated analog inputs. In the default configuration, the brown and orange flying leads are inputs that control the PD’s LED, the blue flying lead is an input that controls the PD’s buzzer, the yellow flying lead is an output that indicates tamper, and the purple and grey flying leads are analog inputs used for configuration.
The OSM-CPI and compatible attached peripheral devices can be configured in various ways by shorting certain combinations of the flying leads together at power-up.
An OSM-CPI connected peripheral device can be “paired” together, by shorting the purple flying lead to ground before power up. The OSM-CPI will initiate a secure channel session using SCBK_D , then issue an osdp_KEYSET command with a new random key. From then on, during normal operation, the OSM-CPI will initiate secure channel sessions using only that key.
An OSM-CPI connected to a compatible peripheral device can both be restored to a factory default state, by shorting the purple flying lead to ground, and shorting the green flying lead to the yellow flying lead before power up. The OSM-CPI will send manufacturer specific commands to the peripheral device that will cause it to be restored to a factory default state, then restore itself to a factory default state.
An OSM-CPI can be configured to emulate a peripheral device for further configuration, by shorting both the purple and grey flying leads to ground before power up.
When power is first applied, the OSM-CPI will indicate that it is powering up by cycling it’s diagnostic LED through 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 odsp_POLL command. It will continue to send osdp_POLL commands at about 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 reply to this command is not as expected, or never arrives, the OSM-CPI 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 not as expected, or never arrives, the OSMCPI will restart the connection sequence from the beginning.
After communication initalization, 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:
If the OSM-CPI’s buzzer input changes from high to low, it will send an osdp_BUZ command with the following payload: 0x0002010000 , setting the state of the PD ‘s reader 0’s buzzer to a continous default tone.
If the OSM-CPI’s input 1 line changes from low to high, it will send an osdp_BUZ command with the following payload: 0x0001000000 , setting the state of the PD ‘s reader 0’s buzzer to off.
If the OSM-CPI receives an osdp_RAW reply, it will extract and output the reader data from that message using the Wiegand interface.
If the OSM-CPI receives an osdp_KEYPAD reply, it will extract and output the keypad data in 8 bit burst mode, detailed in the following table: