Coded data generation or conversion – Digital code to digital code converters
Reexamination Certificate
2001-10-10
2004-02-10
Young, Brian (Department: 2819)
Coded data generation or conversion
Digital code to digital code converters
C370S466000, C370S401000
Reexamination Certificate
active
06690304
ABSTRACT:
TECHNICAL FIELD
This invention relates to a protocol conversion apparatus and protocol conversion method for selecting a protocol for data transmitted between a plurality of terminals to be the most suitable protocol at each terminal or a network, and performing adjusting operation between protocols of each terminal.
BACKGROUND ART
FIG. 16
shows an applied connection example of a conventional protocol conversion apparatus disclosed in the Unexamined Japanese Patent Publication 11-127216.
FIG. 17
shows an internal configuration of the conventional protocol conversion apparatus.
FIG. 18
is a flowchart showing operations performed by the conventional protocol conversion apparatus.
In
FIG. 16
, the following are shown: a terminal A
10
connected to a closed area network, a terminal B
20
connected to a public network, a protocol conversion apparatus
30
which connects the terminals A and B by converting protocols when necessary, a closed area network
40
for connecting the terminal A and the protocol conversion apparatus, and a public network
50
for connecting the terminal B and the protocol conversion apparatus.
In
FIG. 17
, the following are shown: a control unit
100
for controlling the protocol conversion apparatus, and for sending and receiving control signals to/from the terminals, and a closed area network interface unit
110
for interfacing with the closed area network. The closed area network interface unit
110
sends/receives main data to/from a switching unit in the apparatus, and sends/receives control signals for the terminals to/from the control unit. A public network interface unit
120
for interfacing with the public network is also shown. The public network interface unit
120
sends/receives main data to/from the switching unit in the apparatus, and sends/receives control signals for the terminals to/from the control unit. A switching unit
130
for connecting cards for a transmission of main data, a control signal
200
from the terminal A or the closed area network, a control signal
210
from the terminal B or the public network, a main data signal
220
transmitted between the terminal A and the terminal B, and a protocol conversion unit
310
for converting PCM speech data of 64 Kbps to compressed speech data of 8 Kbps are also shown in FIG.
17
.
Now, operations will be explained. With reference to
FIGS. 16 and 17
, it is supposed that the terminal B
20
transmits signals and the terminal A
10
receives the signals. The control signal
210
indicating a transmission of signals from the terminal B
20
is input into the public network interface unit
120
of the protocol conversion apparatus
30
, and the information is forwarded to the control unit
100
from the public network interface unit
120
. The control unit
100
analyzes the contents of the control signal
210
and detects the type of a bearer required to be used for transmission.
When the bearer requested by the terminal B
20
is non-restricted digital data of 64 Kbps, the control unit controls the switching unit
130
in order to establish a path for the main data
220
on a non-restricted digital bearer of 64 Kbps between the public network interface unit
120
and the closed area network interface unit
110
.
On the other hand, if the bearer requested by the terminal B
20
is speech, the control unit directs the switching unit
130
and a suitable protocol conversion unit
310
to set up a path for the main data
220
through the public network interface unit
120
, the protocol conversion unit
310
, and the closed area network interface unit
110
.
In this case, the protocol conversion unit
30
performs a mutual conversion between the PCM speech signal of 64 Kbps and the compressed speech signal of 8 Kbps. Thus, the PCM speech signal of 64 Kbps can be transmitted between the terminal B
20
and the protocol conversion apparatus
310
, and the compressed speech signal of 8 Kbps can be transmitted between the protocol conversion apparatus
30
and the terminal A
10
.
In the case of an image terminal, a FAX, a MODEM, or others, only a basic bearer is selected based on the control signal at the sending/receiving time, and after the bearer is connected, the connectivity between the terminals is confirmed based on a protocol between the terminals. Then, the protocol which has been confirmed of providing mutual connectivity is used for communications.
However, in the conventional protocol conversion apparatus, the protocol requested by the terminal is judged based only on the contents of control signals from the terminal or the network. It is only possible to judge a basic point, such as whether data output from the terminal is digital data or speech data, based on the contents of the control signals. Therefore, only a conversion for a basic bearer can be performed in the conventional protocol conversion apparatus. Thus, it has been impossible to perform the most suitable protocol conversion.
For instance, when image terminals respectively using different protocols are to be connected, it is just possible to judge that data is non-restricted digital data of 64 Kbps based on the control signal, in the conventional protocol conversion apparatus. Then, at the sequence of confirming the connectivity between the image terminals to be performed later, the protocol which can be used in both the terminals is selected, or the communications is disconnected by the terminals if the connectivity is not confirmed. In usual cases, the best function which the terminal can perform may mostly be limited in the protocol which can be used for both the terminals.
It is one of objects of the present invention to solve the above problem, and it is another object to elicit the function of each terminal as much as possible and to perform the most suitable protocol conversion.
DISCLOSURE OF THE INVENTION
According to one aspect of protocol conversion apparatus of the present invention, the protocol conversion apparatus, connected to a calling side terminal and a called side terminal, for performing protocol conversion between the calling side terminal and the called side terminal, comprises:
a protocol conversion unit for performing protocol conversion between a calling side protocol of the calling side terminal and a called side protocol of the called side terminal;
a signal detect unit for detecting a connectivity confirmation signal transmitted between the calling side terminal and the called side terminal; and
a control unit for specifying the calling side protocol and the called side protocol based on the connectivity confirmation signal detected by the signal detect unit;
wherein the protocol conversion unit can perform protocol conversions of plural types,
wherein the control unit selects one protocol conversion out of the protocol conversions of plural types performed by the protocol conversion unit, based on a specified calling side protocol and a specified called side protocol, and
wherein the protocol conversion unit performs the protocol conversion selected by the control unit.
According to another aspect of protocol conversion apparatus of the present invention, the protocol conversion apparatus, connected to a calling side terminal and a called side terminal, for performing protocol conversion between the calling side terminal and the called side terminal,
the protocol conversion apparatus further connected to a protocol conversion software database storing a plurality of protocol conversion software of plural types corresponding to protocol conversion types, the protocol conversion apparatus comprises:
a protocol conversion unit for performing protocol conversion between a calling side protocol of the calling side terminal and a called side protocol of the called side terminal;
a signal detect unit for detecting a connectivity confirmation signal transmitted between the calling side terminal and the called side terminal; and
a control unit for specifying the calling side protocol and the called side protocol based on the connectivity confirmation signal detected by the signal detect
Itou Syuuji
Shirokura Yoshihiko
Mitsubishi Denki & Kabushiki Kaisha
Nguyen John
Rothwell Figg Ernst & Manbeck
Young Brian
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