<Tr> <Td> Beacon BCN </Td> <Td> </Td> <Td> Not part of HDLC </Td> <Td> Was part of SDLC </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <P> The UI, XID, TEST frames contain a payload, and can be used as both commands and responses . The FRMR response also contains a payload . </P> <Ul> <Li> A UI frame contains user information, but unlike an I frame it is not acknowledged or retransmitted if lost . </Li> <Li> The XID frame is used to exchange terminal capabilities . IBM Systems Network Architecture defined one format, but the variant defined in ISO 8885 is more commonly used . A primary advertises its capabilities with an XID command, and a secondary returns an XID response . </Li> <Li> The TEST frame is simply a ping command for debugging purposes . The payload of the TEST command is returned in the TEST response . </Li> <Li> The FRMR response contains a description of the unacceptable frame, in a standardized format . The first 1 or 2 bytes are a copy of the rejected control field, the next 1 or 2 contain the secondary's current send and receive sequence numbers, and the following 4 or 5 bits indicate the reason for the rejection . </Li> </Ul> <Li> A UI frame contains user information, but unlike an I frame it is not acknowledged or retransmitted if lost . </Li>

List and explain the different types of frames in hdlc