1.17.2 Door OpenDescriptionAn extension user can unlock the door for a visitor using his telephone.The door can be unlocked by extension users who are allowed to unlock the door through COS programming.However, while engaged on a doorphone call, any extension user can unlock the door to let the visitor in (®1.17.1 Doorphone Call).Conditions• Hardware Requirement: A user-supplied door opener on each door.• The door opener will unlock the door even if a doorphone is not installed.• Door Open DurationThe door can remain unlocked for a preprogrammed time period.Installation Manual References2.8.1 Connection of Doorphones, Door Openers, External Sensors, and External RelaysPC Programming Manual References4.4 [2-3] Timers & Counters—DISA / Door / Reminder / U. Conf— Doorphone—Open Duration4.8 [2-6-1] Numbering Plan—Main—Features— Door Open4.11 [2-7-1] Class of Service—COS Settings—Optional Device & Other Extensions— Door UnlockPT Programming Manual References[207] Door Unlock Time[512] Permission for Door Open AccessFeature Guide References2.2.1 Class of Service (COS)User Manual References1.10.1 If a Doorphone/Door Opener is Connected184 Feature Guide1.17.2 Door Open