Multi-Tech Systems MT5634SMI V.92 manual Parameter Commands, Session Parameters, +Fcc=, +Fdcc=

Chapter 3 – Fax Class 2 Commands

Parameter Commands

All Class 2 parameters can be read, written, and tested for the range of legal values by the modem. The general syntax is described in the AT Command section of this Chapter.

T.30 Session Parameters

Group 3 fax devices negotiate session parameters in the DIS, DCS and DTC frames. The following parameters are provided to condition the fax modem for the capabilities it will offer, and to report the negotiated session settings.

The three primary T.30 session parameters are +FCC [FDCC], +FIS [FDIS] and +FCS [FDCS], described in 2.5.1.1–2.5.1.3. These are compound parameters using values listed in Table 3.5. The Figure below illustrates their relationships:

DTE Wr ite

DTE Read

DTE Wr ite DTE Report DTE Read

DTE Wr ite

DTE Read

+FCC

DCE Capabilities

Cold	Write		End of
Start	+FDCC		Session
					DIS/DTC if receive
+FIS				Virtual DIS
DCE Negotiating
Position				on send
						DIS/DTC
0,0,0,0,0,0,0,0						from remote
					On send,
						station
	Cold	End of			determine
					DCS in
	Start	Session
					fax DCE
+FCS Negotiated					DCS if send
Session Parameters
					Remote DCS on receive

	T.30 session parameters
Modem Capabilities Parameters
Class 2.1	+FCC=
Write Syntax:	+FCC=VR,BR,WD,LN,DF,EC,BF,ST,JP
Values:	See Table 3.5
Default:	1,5,0,2,0,0,0,0
	+FCC allows the host to sense and constrain the capabilities of the facsimile modem,
	from the choices defined in ITU-T T.30. When +FCC is modified by the host, the
	modem will copy +FCC into +FIS.
	Note: The Multi-Tech implementation does not include the T.32 subparameter WD 3
	and 4 values or the EC 2 and 3 values; also, for subparameter BF only the 00 value
	is implemented.
Class 2	+FDCC=
Write Syntax:	+FCC=VR,BR,WD,LN,DF,EC,BF,ST
Values:	See Table 3.5.
Default:	1,5,0,2,0,0,0,0
	The Class 2 parameter is essentially the same as the Class 2.1 parameter except
	that it lacks the JP subparameter, and the modem copies +FDCC into +FDIS.

Multi-Tech Systems, Inc. SocketModem MT5634SMIxx Reference Guide (S000263C) 72