Epson MFJ-1278B manual Rnr, Rej, Sabm, Disc, Frmr

MFJ-1278B MULTI-MODE PACKET RADIO PROTOCOL

RNR

The RNR frame is used when the buffer space on the receiving side is full.

REJ

Used to request retransmission of frames starting from "x". Missed frames are detected by receiving a frame number different from that expected.

DM

Sent in response to any frame received other than a connect request (SABM) when the TNC is disconnected. Sent in response to an SABM whenever the TNC is on the air but can't connect to the requesting user, e.g., if the TNC is already connected to someone else or if CONOK is OFF.

SABM

Set Asynchronous Balanced Mode - initiates a connect.

DISC

Initiates a packet disconnect sequence.

UA

Sent to acknowledge receipt of an SABM or DISC.

FRMR

Sent when an abnormal condition occurs, i.e., the control byte received is undefined or not proper protocol at the time received.

UI

An I frame without a frame number. It is not acknowledged.