Communication apparatus

Details Communication apparatus Communication apparatus

1998-08-05

2001-10-23

Moore, David (Department: 2624)

Facsimile and static presentation processing

Static presentation processing

Communication

C358S434000, C358S436000

Reexamination Certificate

active

06307642

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a communication apparatus, for example, a facsimile machine, which executes communication according to the protocols that are defined by Recommendations T.30, V.8 and V.34 of the ITU-T (International Telecommunication Union for Telecommunications).
2. Description of the Related Art
Recommendation T.30 of the ITU-T defines a protocol for transmitting text via facsimile over a public switched telephone network(PSTN), Recommendation V.8 specifies a session start protocol for data transmission over the PSTN, and Recommendation V.34 defines the specifications of a modem which operates at a data signal rate of up to 33600 bps that is used in the PSTN and a 2-wire, point-to-point telephone-type private line.
FIG. 13
is a diagram showing a protocol signal in a communication apparatus according to first prior art. Here, a calling station and a called station are both operable according to the protocols of Recommendations T.30, V.8 and V.34 of the ITU-T. After a line connection between the calling station and called station is established, the called station transmits a modulated answer tone signal(ANSam). Upon reception of the ANSam signal, the calling station transmits a calling menu signal(CM signal). When the called station receives the CM signal within a predetermined ANSam transmission time t
1
defined by Recommendation V.8, the called station transmits a common menu signal(JM signal). A modulation mode between the calling station and the called station is determined by exchanging the CM signal and the JM signal. Upon reception of the JM signal, the calling station transmits a calling menu end signal(CJ signal), which is in turn received by the called station. After the calling station and called station complete the protocol of Recommendation V.8, the protocol of Recommendation V.34 is carried out.
FIG. 14
is a diagram showing a protocol signal in a communication apparatus according to second prior art. In this prior art, a calling station and a called station can also operate according to the protocols of Recommendations T.30, V.8 and V.34. After a line connection between the calling station and called station is established, the called station transmits an ANSam signal. When the calling station does not receive the ANSam signal and thus transmits no CM signal, the called station cannot receive the CM signal within the predetermined ANSam transmission time t
1
. At this time, the called station interrupts transmission of the ANSam signal and transmits a digital identification signal(DIS) in which bit
6
is set, i.e., bit
6
=1. Upon reception of the DIS, the calling station transmits a calling indication signal(CI signal). When receiving the CI signal, the called station transmits the ANSam signal. After the calling station receives the ANSam signal, the protocols of Recommendations V.8 and V.34 are executed as illustrated in FIG.
13
.
FIG. 15
is a diagram showing a protocol signal in a communication apparatus according to third prior art. Here, a called station can operate according to the protocols of Recommendations T.30, V.8 and V.34, while a calling station can operate according only to the protocol of Recommendation T.30. After a line connection between the calling station and called station is established, the called station transmits an ANSam signal. When the calling station does not receive the ANSam signal and thus transmits no CM signal, the called station cannot receive the CM signal within the predetermined ANSam transmission time t
1
. At this time, the called station interrupts transmission of the ANSam signal and transmits a DIS with bit
6
set. Upon reception of the DIS, the calling station transmits a digital command signal(DCS) or a non-standard facilities set-up signal(NSS), and the called station receives the DCS or NSS. In this manner, the calling station and the called station execute the protocol of Recommendation T. 30.
FIG. 16
is a diagram showing a protocol signal in a communication apparatus according to fourth prior art. Here, a called station is operable according only to the protocol of Recommendation T.30, while a calling station is operable according to the protocols of Recommendations T.30, V.8 and V.34. After a line connection between the calling station and called station is established, the called station transmits an answer tone signal(ANS signal). The calling station does not receive the ANS signal and does not therefore transmit a CM signal. The called station transmits the ANS signal for a predetermined ANS transmission time t
2
defined by Recommendation V.25, and then transmits a DIS with bit
6
reset, i.e., a DIS with bit
6
=0. The calling station, when receiving the DIS, transmits a DCS or NSS, and the called station receives the DCS or NSS. In this manner, the calling station and the called station execute the protocol of Recommendation T.30.
Some examples of such communication apparatuses are disclosed in, for example, Japanese Unexamined Patent Publications JP-A 8-79483 (1996), 7-298027 and 8-214132 (1996). In JP-A 8-79483, a communication apparatus operable according to the protocol of Recommendation V.8 is permitted to receive data both from a station which is operable according to the protocol of Recommendation V.8 and a station which is operable according to the protocol of Recommendation T.30 in the following manner. When receiving the CM signal within the ANSam transmission time t
1
, the apparatus transmits the JM signal to execute the protocol of Recommendation V.8. When the apparatus cannot receive the CM signal within the ANSam transmission time t
1
, on the other hand, the apparatus transmits an nonstandard facilities signal(NSF signal), a called subscriber identification signal(CSI signal) and DIS, and upon reception of the CM signal thereafter, the apparatus transmits the JM signal and then executes the protocol of Recommendation V.8, while upon reception of the NSS, transmitting subscriber identification signal(TSI signal) and DCS, the apparatus executes the protocol of Recommendation T.30.
In Japanese Unexamined Patent Publication JP-A 7-298027 (1995), in order to enable a subscriber terminal operative according to the protocol of Recommendation V.8 and a subscriber terminal inoperative according to the protocol of Recommendation V.8 to communicate with each other, a communication apparatus operative according to the protocol of Recommendation V.8 transmits a CI signal after transmission of a calling tone signal(CNG signal), and thereafter upon reception of an AI signal or ANSam signal, executes the protocol of Recommendation V.8 after transmission of the CM signal, whereas when receiving the NSF, CSI and DISs, the apparatus executes the protocol of Recommendation T.30 after transmission of the NSS, TSI and DCS. Further, in JP-A 8-214132 (1996), to effectively utilize Recommendation V.8, the communication apparatus transmits the CM signal upon reception of the ANSam signal from a called station, and transmits the CJ signal upon reception of the JM signal from the called station.
Japanese Unexamined Patent Publication JP-A 8-214136 (1996) discloses that when a transmitting subscriber terminal can not receive a JM signal from a called station during a predetermined period of transmission of a CM signal, the transmitting subscriber terminal executes switching among transmission modes so that the JM signal is received in the half duplex transmission mode after transmission of the CM signal and in the case where a CJ signal is transmitted after reception of a JM signal at a calling station a called subscriber terminal executes switching among transmission modes, when the CM and CJ signals can not be received during transmission of the JM signal, so that the transmission period of the JM signal is extended and the CJ signal from the calling subscriber terminal is received in the half duplex transmission mode.
FIG. 17
is a diagram depicting a protocol signal for the conventional communication apparatuses when a c

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