The DCE holds the post page response message to the remote facsimile
station (MCF, etc.), represented in the +FPTS parameter until the next
+FDR command. The DTE may modify the +FPTS parameter before issuing the
+FDR command which releases that message. The DTE must issue a +FDR
command to release Post Page Messages.
INITIATE DOCUMENT RECEPTION
The +FDR command may be issued in Phase B after an answer command, or in
Phase B after a pervious document.
The DCE response in stream mode is:
+FCR ; when CFR sent
[+FTSI:<remote ID string>] ; if new TSI received
+FDCS:<T.30 subparameter string>] ; if new DCS
CONNECT
(<DC2> needed from DTE here)
<Phase C data stream>
<DLE><ETX>
+FPTS:<ppr>,<lc>[,<blc>,<cblc>]
+FET:<ppm>
OK
(DTE must issue +FDR command to release post page response)
CONTINUE DOCUMENT RECEPTION
The DTE may issue a +FDR command in Phase D, which releases the post
page message, and indicates readiness to receive another page after
receipt of a Multipage (+FET:0) or PPS-NULL (+FET:3) message. The DCE
response will be:
CONNECT
(<DC2> needed from DTE here)
<Phase C data stream>
<DLE><ETX>
+FPTS:<ppr>,<lc>[,<blc>,<cblc>]
+FET:<ppm>
OK
(DTE must issue +FDR command to release post page response.
If done receiving:
+FHNG:<hangup cause code>
OK
Continue page reception
PHASE C DATA FRAMING
Phase C data may be presented to the DTE in stream mode. The DCE will
transfer a stream of data to the DTE, followed by the <DLE><ETX> stream
termination characters. The DCE will filter the stream as described in
7.1.2.
PHASE C DATA FORMAT
The received data format is negotiated under T.30 reported by the
+FDCS:VR,BR,WD,LN,DF,EC,BF,ST response.
The DCE will delete the terminating RTC (6 EOLs) patterns. The DCE may
strip zero fill bits from the data, to minimize storage needs.
<CAN>, ESCAPE FROM RECEPTION
From the +FDR command until the end of Phase D Date, the DCE is in a
data transfer state, and will not respond to DTE command characters.
The DCE will respond to three ASCII control characters, <DC1 (017) and
<DC3> (019) flow control characters, and cancel <CAN> (024).
Upon receipt of the <CAN> character, the DCE will terminate the
reporting of received data by sending trailing <DLE><ETX> characters to
the DTE, and will then execute an implied +FK command in order to
conduct an orderly disconnection.
7.3.6 +FK, SESSION TERMINATION
Syntax: +FK
The +FK command causes the DCE to terminate the session in an orderly
manner. In particular, the DCE will send a DCN message at the next
opportunity and hang up. At the end of the termination process, the DCE
will report the +FHNG response with result code (Table 7-5).
This operation can be invoked by using the cancel <CAN> character during
Phase C data reception (see prior section).
The DCE will wait until the current page completes, unless the reception
is of unlimited length; in that case, the DCE may halt reception and
terminate the session at any time.
7.4 SERVICE CLASS 2 DCE RESPONSES
The DCE sends information responses to the DTE as a facsimile session
proceeds. They indicate the state of the facsimile session and convey
need information. These messages are solicited messages generated in
execution of DTE action commands described in section 7.3.
The DCE precedes and follows the following information responses with
<CR><LF>.
The DCE provides the on-line status of several session parameters when
they are available during T.30 handshaking. These include the remote ID
string and the DIS/DCS parameters. These responses report the T.30
session parameter frames. The subparameters are described in Table 7-2.
7.4.1 +FCON, FACSIMILE CONNECTION RESPONSE
+FCON indicates connection with a fax machine. It is released by
detection of HDLC flags in the first received frame +FCON is generated
in response to an Originate or Answer command.
7.4.2 +FDCS:, REPORT CURRENT SESSION CAPABILITIES
Syntax: +FDCS:VR,BR,WD,LN,DF,EC,BF,ST
+FDCS:<string> reports the negotiated parameters. Phase C data will be
formatted as described by the subparameters. This message may be
generated in execution of +FDT or +FDR commands before the CONNECT
result code if new DCS frames are generated of received. (See Table 7-
2.)
7.4.3 +FDIS:, REPORT REMOTE STATION CAPABILITIES
Syntax: +FDIS:VR,BR,WD,LN,DF,EC,BF,ST
+FDIS:<string> reports remote facsimile station capabilities and
intentions. The parameters are provided in ASCII notation. (See Table
7-2.)
This message is generated in execution of Originate, Answer, +FDT, or
+FDR commands.
7.4.4 +FCFR, INDICATE CONFIRMATION TO RECEIVE
Syntax: +FCFR
The DCE sends a +FCFR response to the DTE upon reception of an
acceptable TCF training burst and a valid DCS signal from the remote
machine. This indicates that the DCE will receive Phase C data after
the remote station receives the local DCE's CFR message. The +FCFR
message is generated in execution of a +FDR command.
7.4.5 +FTSI:, REPORT THE TRANSMIT STATION ID
Syntax: +FTSI:"<TSI ID string>" Transmit Station ID
This response reports the received transmit station ID string, if any.
This message is generated in execution of Originate, Answer, +FDT, or
+FDR commands.
7.4.6 +FCSI:, REPORT THE CALLED STATION ID
Syntax: +FCSI:"<CSI ID string>" Called Station ID
This response reports the received called station ID string, if any.
This message is generated in execution of Originate, Answer, +FDT, or
+FDA commands.
7.4.7 +FPTS:, RECEIVE PAGE TRANSFER STATUS
Syntax: +FPTS:<ppr>,<lc>[,<blc>,<cblc>]
The +FPTS:<ppr> is generated by the DCE at the end of Phase C data
reception in execution of a +FDR command.
The <ppr> is generated by the DCE; it depends on the DCE capabilities at
T.4 error checking. See Table 7-4 for <ppr> values.
The receiving DCE will count the lines and may optionally generate bad
line counts. These values are:
<lc> = line count
<blc> = bad line count
<cblc> = <consecutive bad line count
A receiving DTE may inspect <ppr> and write a modified value into the +FPTS parameter. The DCE will hold the corresponding Post Page Response message until released by a +FDR command from the DTE.
7.4.8 +FET:, POST PAGE MESSAGE RESPONSE
Syntax: +FET:<ppm>
The +FET:<post page message> response is generated by a receiving DCE
after DCE after the end of Phase C reception on receipt of the post-page
message from the transmitting station. The +GET:<ppm> response is
generated in execution of a +FDR command. The <ppm> codes respond to
the T.30 pst page messages (Table 7-3)
7.4.9 +FPTS:, TRANSMIT PAGE TRANSFER STATUS
Syntax: +FPTS:<ppr>
The +FPTS: response reports a <ppr> number representing the copy quality
and related post page message responses received from the remote DCE.
The set of valid <ppr> values are defined in Table 7-4.
The +FPTS:<ppr> response is generated in execution of a +FET=<ppm>
command.
7.4.10 +FHNG:, CALL TERMINATION WITH STATUS
Syntax: +FHNG:<hangup status code>
+FHNG indicates that the call has been terminated. The hangup cause is
reported and stored in the +FAXERR parameter for later inspection. The
<hangup status code> values are described in Table 7-5.
+FHNG:<hsc> is a possible intermediate result code to any DTE action
command described in Section 7.3. It is always followed by the OK final
result code.
Upon termination of a call, the DCE determines the cause of termination
and reports it as part of the FHNG:<hsc> response. It also stores this
<hsc> code in the +FAXERR parameter for later inspection.
The hangup values are organized according to the phases of the facsimile
transaction as defined by T.30. A COMREC error or RSPREC error
indicates that one of two events occurred. 1) a DCN (disconnect) signal
was received, or 2) an FCS error was detected and the incoming signal
was still present after 3 seconds.
The table values are in decimal notation. Leading zero characters are