If youre interested in having a more in depth look at how it works take a look at this osdp protocol example diagram which gives an insight into how to use it with existing wiegand devices. This includes how to connect both a peripheral device pd or access control unit acu or both.

Access Control Systems Integrated Security Solutions
Osdp reader wiring diagram. Ease of use audio visual user feedback mechanisms provide a rich user centric access control environment. It is possible to reuse existing wiegand wiring for osdp. The maximum cable length is 2000 ft. While wiegand has been the de facto standard for decades osdp aims to solve major problems of wiegand. However using simple stranded cable typical of wiegand access control readers does not typically meet the tia485eia rs485 specification for twisted pair recommendations. Upon power up you have 5 seconds to enter the facility code followed by.
Access control readers and controllers need to communicate. If unsuccessful the reader led displays solid red. With a keypad reader operating as 26 bit emulation. 244 if upgrading a wiegand reader to osdp do you need to also change the wiring as well. All kinds of osdp devices including sensors actuators io boxes even controllers can be connected over the same 2 wire cable. Provides up to 15 a of power at door for reader lock and more.
In particular osdps benefits. If facility code is 10 enter 0 1 0. In addition osdps multi drop capabilities means one length of 2 conductor cable can accommodate many readers eliminating the need to run wire for each reader. The nsc 200 is a series 3 subcontroller that can have up to 4 doors 2 in and 2 outs connected to subcontroller via rs. Supports multiple card formats paired and alternate readers elevator turnstile and biometric devices. If you work in access control no doubt you realize that wiegand became a de facto industry standard after it first emerged in the early 1980s but has not kept pace with todays.
Reader port 1 can support up to eight 2 wire rs 485 remote serial io devices using msp1 protocol or up to two osdp devices. What is the wiring diagram for osdp. Osdps use of 2 wires instead of 12 allows for multi drop installation supervised connections to indicate reader malfunctions and scalability to connect more field devices. If two osdp devices are used reader port 2 will not support a third reader. Anti passback support area reader and time based programmable keypad user commands. If only one osdp device is configured then reader port 2 is available for a second reader.
What secure channel means for osdp. Performance and wiring differences between wiegand and osdp. Included in this technical bulletin are wiring diagrams and instructions on properly configuring hid osdp readers with an nsc 200 subcontroller. Instead of using discrete wires osdp works over a communication bus and can be used for much more than connecting a single card reader. The facility code needs to be manually entered as 3 digits ie. Osdp wiring is simpler.
Power cycle the reader and retry entering the facility code.