Modem User Manual

Chapter 3 – Fax Class 2 Commands

Multi-Tech Systems, Inc. SocketModem MT5634SMIxx Reference Guide (S000263C) 93

Session Message Report Responses

The modem may be commanded to report the T.30 Phase B and Phase D HDLC control frames as

they are sent and received. This service supports session diagnostics and the debugging of host

software. It is enabled by the +FBU parameter described in the Parameter Commands section of this

chapter.

These messages are not generated in direct execution of host action commands; they are generated

for each frame whenever the reported frame is sent or received. The host should not attempt to

change serial port speed or parity with +FBU set. It is desirable to suppress echo of host commands,

if the modem provides that facility.

The data will be reported with each T.30 command separated by <CR><LF>. The fill bits will be

removed. The frame octets will be represented in hex notation, and separated by spaces. Flags and

zero bits are removed. Frame octets are reported in the order sent or received. FCS bytes are

deleted. Frame octets are presented with the LSB as the first bit sent or received.

The following is an example of a received DIS string report:

+FHR: FF 13 80 00 4E 78 FE AD<CR><LF>

Unless specified otherwise, the modem reports these frames before the corresponding responses are

generated. For example, the above examples would occur before the standard +FIS: report was