| Anti pass-back | Where the turnstile provides a return signal to the Access Control System to signal that user A has entered or exited the building. If user A then passes his proximity card to user B the access control system will know that this entry is potentially fraudulent and prevent access/egress. |
| Anti-piggybacking | Where methods have been put in place to avoid unauthorized people gaining access to a secured area by passing through in collusion with another person who does have authorization. |
| Anti-tailgating | Where measures have been taken to avoid an unauthorized person following another through a secured entrance way, therefore achieving access without the authorized person’s knowledge or consent. |
| Biometric Control | The use of biological features i.e. Fingerprints, eyes, voice etc to ensure that the user is carrying their access control card and that fraudulent entry is not being gained by a 3rd party |
| Breakaway force | The level of force, required by the turnstile user, to collapse the turnstile barrier or barriers to allow emergency escape. |
| DDA | Indicates whether a particular product is capable of allowing use by a disabled person. Previously this related to The Disability Discrimination Act, 1995. The applicable Act (except in Northern Ireland) is now The Equality Act 2010. |
| Egress | The exit of a user from a building through a turnstile. |
| Fail Safe | The turnstile will collapse or release all locking to allow non-secure egress during an emergency situation. Used in the majority of situations as part of a cohesive fire strategy. |
| Fail Secure | During an emergency situation the turnstile will ensure that any user is not `trapped’ within the unit before locking to ensure that security is maintained in all situations. |
| Ingress | The entry of a user into a building through a turnstile |
| Optical turnstiles | Turnstiles that monitor the number of transactions, and detect unauthorized entry and signal this through an alarm of some form rather than a physical barrier. |
| Return signal | A signal or pulse from a turnstile to signify that a user has activated/used/or carried out an unauthorized passage through the units. |
| Volumetric security | A security measure (normally used to prevent piggy-backing) where the physical volume of the turnstiles user is measured rather than purely the weight. |
| Weight sensing | A method of preventing piggy-backing by the turnstile weighing the occupant(s) of the turnstile during operation. If the weight exceeds the permissible weight of user, access will be denied. |