About single passage enforcement - Synergis™ Softwire 10.5 and later

Synergis Softwire Single Passage Enforcement Technote

Synergis™ Softwire 10.5 and later

Single passage enforcement is a Synergis™ Softwire feature that ensures that no more than one person can enter or exit an area per access grant, provided that the access to the area is controlled with a turnstile or a similar device that allows only one person through at a time.

Single passage enforcement requires Security Center 5.2 or later, and a Synergis™ unit running SMC 2.2 GA and later, or Synergis™ Softwire 10.0 GA and later.

To enforce single passage on doors controlled by a Mercury EP unit, you need Synergis™ Softwire 10.2 GA and later.

Benefits of single passage enforcement

Single passage enforcement can be used to improve the accuracy of people-counting and antipassback by effectively preventing tailgating, instead of just detecting it.

How this feature works (in general)

When single passage is enforced on a perimeter door, the Synergis™ unit applies the following additional rules:
  • When a cardholder presents their credential at the door and is granted access, all subsequent credentials presented at the door reader are ignored for either a period equivalent to the Standard grant time + Entry time configured for the door, or until a passage through the door is detected (whichever comes first).

    If the cardholder is entitled to extended grant time, the reader shunting period is calculated as the Extended grant time + Entry time configured for the door.

    The Entry time is only taken into consideration if an entry sensor is configured for the door.
  • When a cardholder presents their credential at the door and is denied access, the next cardholder that presents a valid credential is granted access without any delay.

How this feature works on doors controlled by Mercury EP units

For doors controlled by Mercury EP units, Synergis™ Softwire uses the Turnstile feature supported by Mercury. Mercury EP supports two turnstile behaviors, called mode 1 and mode 2. The Mercury Turnstile feature behaves slightly differently from the single passage enforcement feature supported by Synergis™ Softwire. In either of the two Mercury turnstile modes, when a cardholder is granted access at a door, or a door is unlocked from Security Desk, the door strike output is activated for 1 second.
The two modes differ in terms of what happens when another cardholder is granted access before the first cardholder passes through the turnstile (Door opened/closed events being received). In the first mode, the Mercury EP unit immediately activates the door strike output for every granted access. In the second mode, the Mercury EP unit only activates the door strike once on the first access grant, and ignores subsequent access grants for the duration of the grant time, unless the door is opened. However, if a valid credential is presented while the door is open, and door closes within the grant time, the unit activates the door strike again.


Only single-reader doors (turnstiles) are supported, meaning that the passage through the barrier is controlled in only one direction.