Specifications

Alto 818 Installation and Operation
1-10 P/N 66109074001 Rev. D
HARD A NTI-PASSBACK
When hard passback is used, failure to alternate between entry and exit causes a data log entry
to be printed and access to be denied.
SOFT ANTI-PASSBACK
A soft anti-passback violation causes a data log entry to be printed but access is granted if the
card key is otherwise valid.
REX AND DS CONSIDERATIONS
When an area is anti-passback controlled, a REX switch is not used at the doors. Separate doors
can be used for entering and exiting or the same door may be used with readers on each side.
If an anti-passback-controlled door is not monitored by a door switch, then the ACU assumes that
whenever a command key is presented to a sensor, the key holder will complete access through
that door. If access of the key holder is interrupted, he or she cannot repeat key presentation
without a passback violation. Use of a door switch ensures that the Alto 818 will wait until the door
opens, as signaled by the door switch, before changing the key holder status. For this reason,
use of a door switch is recommended in anti-passback operations.
ANTI-PASSBACK S TATUS
When the Alto 818 is configured for anti-passback control at a specific door, the anti-passback
status of each command key user is automatically reset from OUT to IN when the user gains
entrance to a controlled area. Conversely, key holder status will be reset from IN to OUT when
the key holder uses his or her command key to leave the controlled area.
Anti-passback status can be reset to UNKNOWN for all key holders by use of the FORGIVE
command or for an individual key holder by use of the KEY command. If power to the ACU is lost,
the status for all key holders is set to UNKNOWN.
TYPICAL ANTI-PASSBACK I NSTALLATION
A typical anti-passback installation is shown in Figure 1-1. Door 1 uses a one-way mechanical
turnstile which permits entrance when an authorized command key is presented to reader 1. Door
2 uses a turnstile which will permit exit when an authorized command key is presented to reader
2. Door 3 is used for two-way traffic; Reader 4 controls the entrance to the area while reader 3
controls exiting. All three entries have door switches.