Multi-Drop Bus

The multidrop bus is a machine interface, which is needed to connect Münzgeldwechslern and bill validators or cashless payment systems. It is used for example in beverage or cigarette.

Function

The standard was issued and defines both the physical interface ( electrical specifications), as well as the communication process between the participants from the American National Automatic Merchandising Association.

The communication is based on the master-slave principle. All slaves are connected with optocouplers to Master Transmit. All slaves are connected via open collector circuit in parallel with Master -Receive and again galvanically isolated by optocouplers. The transmission rate is 9600 bps and 32 slaves can be addressed. The master polls the slaves which bus collisions are excluded.