DF-1 Protocol

DF-1 / DF1 protocol is an asynchronous byte-oriented protocol that is used to communicate with most Allen Bradley RS232 interface modules. DF1 protocol consists of link layer and application layer formats. DF1 works over half duplex and full duplex modes of communication.
Application layer messages.
Application layer message format consists of "Command Initiator messages" (request messages) and "Command Executor" (reply messages). Important command initiator messages are as follows.