asynchronous response mode (HDLC) (ARM)

Asynchronous Response Mode(ARM) is an operating mode of the bit-oriented backup protocol HDLC protocol, High Level Data Link Control, with one-way communication control between master station and slave stations.

In this method, the transmission can be initiated by the master station or by a slave station.

ARM mode makes better use of duplex link characteristics than Normal Response Mode( NRM). In this control mode, the slave station can send unsolicited DCE blocks. The control station releases this operating mode with a control block.