Reference · built on requestConnectorIndustrial & building protocols

SIA OSDP

Card reads, keypad entries, input and tamper status from OSDP readers and peripheral devices over RS-485 with Secure Channel.

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About

OSDP, the Open Supervised Device Protocol, is the Security Industry Association's standard for the wire between an access control unit and its readers and peripheral devices. IEC adopted it in 2020 as IEC 60839-11-5, which specifies the communication settings, commands, and replies between the ACU and the peripheral devices. One control panel (CP) polls one or more peripheral devices (PD) over a two-wire, half-duplex RS-485 multi-drop bus. Only the CP speaks unprompted, each message goes to one PD, and the PD must answer within 200 ms. Secure Channel encrypts and authenticates the session with AES-128.

Through Fibric, a gateway acts as the control panel for readers and I/O modules you assign to it. An operator reads card data, keypad entries, inputs, and tamper reports, and proposes an output change or reader feedback for your approval. A receipt records each change, the reason for it, and the way back.

This is a reference listing. It documents what Fibric would read from SIA OSDP and what it could propose, based on the vendor's published interfaces. Fibric builds it under a managed deployment when you request it; selecting it here installs nothing.

Inputs

  • Card data as the PD reports it: osdp_RAW as a raw bit array, or osdp_FMT as a character array
  • Keypad entries in osdp_KEYPAD replies, and biometric data in osdp_BIOREADR where the reader supports it
  • Input and output status from osdp_ISTATR and osdp_OSTATR, requested with osdp_ISTAT and osdp_OSTAT
  • Reader tamper in osdp_RSTATR and local status in osdp_LSTATR
  • Device identity and capabilities from osdp_PDID and osdp_PDCAP, so each reader's features are known before use
  • Supervision: a PD that stops answering within 200 ms, or answers osdp_BUSY or osdp_NAK, is noticed on the next poll

Proposed actions

  • Target capability: propose an output change with osdp_OUT on a PD's relay, for your approval
  • Target capability: propose reader feedback with osdp_LED, osdp_BUZ, and osdp_TEXT, for example a message on the reader display
  • Target capability: propose a Secure Channel key change with osdp_KEYSET when a reader is still on the default key

Proposed actions are target capabilities. Every action runs propose-first and needs a validated deployment and the appropriate permissions.

What you can build

  • Spot a reader that has gone quiet

    Track each PD's replies to osdp_POLL. When one stops answering within 200 ms or reports tamper in osdp_RSTATR, propose a ticket with the reader's address and its last osdp_PDID.

    With Access Anomaly, Audit Trail

  • Retire a credential that keeps failing

    Compare osdp_RAW card data against the credential list from your access system, and propose deactivation for a badge presented at doors it has never used.

    With Badge Hygiene, Access Anomaly

  • Hold a door contact to account

    Read the door contact from osdp_ISTATR. When it stays open past the time you set, propose a reader buzzer with osdp_BUZ and a note for the guard.

    With Door Held Open

  • Finish Secure Channel on every reader

    List readers whose session started from SCBK-Default, and propose a key set with osdp_KEYSET, one reader at a time, for approval.

    With Secret Rotation, Audit Trail

Requirements

  • An RS-485 gateway wired as the control panel for the readers and I/O modules you assign to Fibric
  • Peripheral devices that implement SIA OSDP v2.2 or IEC 60839-11-5, with Secure Channel enabled
  • A unique address and matching baud rate per PD: 9600 to 230400 baud, 8 data bits, 1 stop bit, no parity
  • A Secure Channel Base Key per device, set with osdp_KEYSET after install mode and stored with the gateway
Authentication
Secure Channel: a per-device Secure Channel Base Key (SCBK) held by the control panel, with an AES-128 session negotiated through osdp_CHLNG, osdp_CCRYPT, osdp_SCRYPT, and osdp_RMAC_I.

Limits

  • One control panel per bus, and only it speaks unprompted. This listing cannot listen alongside your existing access control unit
  • Install mode uses SCBK-Default, a key the standard publishes. A reader left on it is not secured until osdp_KEYSET replaces it
  • SIA and IEC sell the specification. The command set here follows the published v2.2 and IEC 60839-11-5 text
  • Manufacturer-specific commands (osdp_MFG) and replies (osdp_MFGREP) sit outside the standard and need the vendor's documentation

Access and pricing

Reference listing. Fibric builds the connector under a managed deployment when you request it. Your quote covers the build, capabilities, usage, and support.

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Questions and answers

Is OSDP an international standard?
Yes. IEC approved it in 2020 and published it as IEC 60839-11-5:2020, Alarm and electronic security systems, Part 11-5: Electronic access control systems, Open supervised device protocol. SIA OSDP v2.2, released in December 2020, is based on that text.
What does Secure Channel protect?
The session between the control panel and a peripheral device. It uses AES with a 128-bit key. The CP sends osdp_CHLNG, the PD answers osdp_CCRYPT, the CP sends osdp_SCRYPT, and the PD closes with osdp_RMAC_I. Session keys derive from the Secure Channel Base Key set with osdp_KEYSET.
Can Fibric read the bus behind my existing access control unit?
No. OSDP is one control panel to one or more peripheral devices, and only the control panel sends unprompted. Fibric acts as the control panel for devices you assign to its gateway. For events from your existing unit, connect that unit's own interface.
Ask about SIA OSDP

Ask about the capabilities and requirements in this listing.

For project-specific requirements, contact Fibric.

This connector listing is developed, published, and supported by Fibric. It describes integration with SIA OSDP through published interfaces. Third-party names and logos identify the systems an integration connects to; they are the property of their respective owners, who are not affiliated with Fibric and do not sponsor or endorse this listing. Trademark policy