A locking mechanism suitable for use with office type chairs comprising an operating lever movable between a locking position in which locking takes place and an unlocking position in which unlocking takes place, a spring, which biases the lever into the locking position and a catch, which holds the lever in the unlocking position upon movement of the lever into the unlocking position. A device interface communicates application data with an application of the handheld wireless communication device via the communication port of the handheld wireless communication device. The AMFs provide concurrent access to the redundancy groups for associated host systems.