Frame. The dormakaba (formerly known as Dorma) TS73EMF is a combination of a hydraulic door closer and an electromagnetic hold-open unit. In conjunction with an alarm / smoke detection system, the TS 73 EMF can be used as a hold-open door closer for fire and smoke check doors. The hold-open of the door is performed under electro-magnetic control. In the event of a fire, the door is reliably closed by the integral hydraulic closer. The closing cycle is also initiated by manual door operation or automatically in the event of a power failure.. Rack-and-pinion door closer with scissor arm for hold-open applications. Can be used as a hold-open system for fire and smoke check doors. Electromagnetic hold-open possible between approx 75° and 180°. Universal solution for doors of differing designs & styles