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Wiring Readers

This page covers landing a card reader on an AccessCore One reader port, setting the per-port protocol jumper, and planning cable runs. The controller has four reader ports — one per door. Each port supports either a Wiegand reader or an OSDP (RS-485) reader, selected by a jumper next to that port.

For the door's other field wiring, see Wiring Locks and REX & Door Contacts. For the OSDP bus topology and the termination jumper, see Networking & OSDP Bus. Every connector on the board is listed in the Terminal & Connector Reference.

Reader ports​

There are four 5-pin reader ports along the left edge of the board, one per door:

Reader portDoorConnector ref
Door 11J14
Door 22J15
Door 33J16
Door 44J17

The silkscreen pin order is identical on all four ports, top to bottom:

Wiring a card reader to the 5-pin reader port — LED, D0/A, D1/B, GND, +12V

Pinout​

PinSilkscreenWiegand useOSDP useTypical reader wire color
1LEDReader LED control lineReader LED control line (if reader exposes one)Brown or Orange
2D0/ADATA0RS-485 AGreen
3D1/BDATA1RS-485 BWhite
4GNDSignal / power groundSignal / power groundBlack
5+12VReader power (~12 V)Reader power (~12 V)Red
caution

The wire colors above are general industry convention only. Always confirm pin function against the reader's own datasheet before landing conductors. Reader manufacturers vary — a mis-landed DATA or power conductor can damage the reader.

Protocol jumper (OP / WD)​

Each reader port has its own protocol jumper next to it, silkscreen OP / WD (refs S1–S4, one per door). This jumper tells the controller which electrical protocol that port runs. Set it per port, to match the reader plugged into that port.

Jumper positionReader typeData pins
WDWiegandD0/A = DATA0, D1/B = DATA1
OPOSDP (RS-485)D0/A = RS-485 A, D1/B = RS-485 B

You can mix reader types across the four doors — set each port's jumper independently. A port set to WD and a port set to OP can run side by side on the same controller.

note

The OSDP/RS-485 transceiver on the reader data lines is galvanically isolated and surge/ESD protected. This isolation is in effect when the port jumper is in the OP position.

Wiring a Wiegand reader​

  1. Set that port's OP / WD jumper to the WD position.
  2. Land reader power: +12 V → +12V, ground → GND.
  3. Land DATA0 → D0/A.
  4. Land DATA1 → D1/B.
  5. If the reader has an LED control line, land it on LED. If it does not, leave LED unconnected.
  6. Dress and clamp the cable; ground the shield at the controller end only (see Cable & distance).

Wiring an OSDP reader​

  1. Set that port's OP / WD jumper to the OP position.
  2. Land reader power: +12 V → +12V, ground → GND.
  3. Land RS-485 A → D0/A.
  4. Land RS-485 B → D1/B.
  5. If the reader has an LED control line and you intend to drive it from the controller, land it on LED. Otherwise leave LED unconnected.
  6. Dress and clamp the cable; ground the shield at the controller end only.

OSDP daisy-chaining and termination​

OSDP is an RS-485 multidrop bus, so one reader port can host a chain of OSDP readers wired in series (A to A, B to B) rather than home-running each reader. Keep the topology as a single linear bus — daisy-chain device to device, and avoid star or stub branches.

The bus must be terminated at both ends only using the OFF / 120 termination jumper. Do not terminate devices in the middle of the chain. Termination, full bus topology rules, and OSDP addressing are covered on the Networking & OSDP Bus page.

:::tip OSDP vs Wiegand OSDP (set jumper to OP) — bidirectional, supervised (the controller knows if a reader goes offline or a wire is cut), supports secure channel encryption, and reaches much longer cable runs. Daisy-chains multiple readers on one port. Prefer OSDP for new installs.

Wiegand (set jumper to WD) — simple, one-way, unsupervised, and universally supported by legacy readers. Each reader home-runs to its own port. Use it when the reader does not speak OSDP or when matching an existing Wiegand head. :::

Reader power and the port fuse​

Each reader port supplies reader power on +12V / GND at roughly 12 V. Each port's +12V output is protected by a self-resetting PTC fuse rated about 0.75 A (refs F1–F4, one per port).

  • If a reader draws more than the port can supply, power the reader from a separate supply and land only the data and (if used) LED conductors on the controller. When you do this, tie the reader supply ground to the port GND so the data reference is common.
  • The PTC fuse is self-resetting: once the overload or short is cleared, the PTC cools and the port restores itself automatically. There is no fuse to replace.
caution

Do not parallel two readers' power onto one port to get more current. If a port can't carry the load, move that reader to an external supply.

Cable & distance​

Present the following as general planning guidance and defer to the reader manufacturer's published cable spec, which always wins:

ProtocolTypical maximum runCable
Wiegand~150 m / 500 ftShielded, 18–22 AWG
OSDP / RS-485~1200 m / 4000 ftShielded twisted pair for the data pair
  • Use shielded cable for both protocols.
  • Ground the cable shield at the controller end only. Grounding both ends creates a ground loop.
  • Run reader cable away from high-voltage and motor/contactor wiring to limit induced noise.

Verify the reader​

  1. With the door wired and the controller powered, present a known-good card or credential at the reader.
  2. The reader acknowledges the credential with its own LED/beep, and a valid card unlocks the door.
  3. Confirm the read appears as an event in the CAK application for the correct door.
  4. If there is no read: re-check the OP / WD jumper matches the reader type, verify D0/A and D1/B are not swapped, and confirm reader power is present on +12V / GND.

Diagram placeholder — reader port with a Wiegand head landed and the OP/WD jumper in the WD position.