ZyXEL Communications Omni 56K II User Manual page 46

Omni 56K II and Omni 56K Plus II User's Guide
Note: If error control result codes are enabled (X4, X5, X6, X7), the resulting message will be formatted as:
X4: CARRIER Rx Rate.
PROTOCOL: Error Control Level
COMPRESSION: Compression Level
CONNECT DTE Speed
X5: CONNECT DTE Speed/Protocol Rx Rate/Error control level
X6: CONNECT Rx Rate/ARQ
X7: CONNECT Rx Rate/ARQ/Error control level
ARQ denotes that the Automatic Retransmission reQuest type of error control is enabled.
4-4 Result Codes