DF1 protocol is an asynchronous byte-oriented protocol that is used to talk with AB RS232 interface modules. DF1 protocol include a link layer and application layer formats.
The Link layer serial frame is a group of conventional RS-232 serial frame with the parameters specified as 8 data bits, no parity, and a maximum baud rate of 19200.
DF1 is ASCII character oriented protocol and works over half duplex and full duplex modes of communication.