APL Field Switch with Automatic Protocol Detection

Protocol detection circuits for detecting the field device protocol of a field device attached to a channel having a data line are sequentially connected to the data line by a controller that communicates to the field device through the protocol detection circuits. The protocol detection circuits are disconnected from the field device after protocol detection is completed. The channel may be one of a number of channels; the controller may also connect and disconnect the protocol detection circuits from the one channel whereby the protocol detection circuits can be used with any channel. After the protocol of the field device is identified a protocol adapter can be inserted into the channel to enable data conversion between the field device protocol and an another protocol used by the channel for data transmission.