Panasonic KX-FT78RU-B / KX-FT78RU-W Service Manual ▷ View online
5.6. MODEM SECTION
5.6.1. FUNCTION
The unit uses a 1 chip modem (IC5), enabling it to act as an interface between the control section for FAX sending and
receiving, and the telephone line. During a sending operation, the digital image signals are modulated and sent to the telephone
line. During a receiving operation, the analog image signals which are received via the telephone line are demodulated and
converted into digital image signals. The communication format and procedures for FAX communication are standardized by
ITU-T. This 1 chip modem (IC5) has hardware which sends and detects all of the necessary signals for FAX communication and
DTMF.
receiving, and the telephone line. During a sending operation, the digital image signals are modulated and sent to the telephone
line. During a receiving operation, the analog image signals which are received via the telephone line are demodulated and
converted into digital image signals. The communication format and procedures for FAX communication are standardized by
ITU-T. This 1 chip modem (IC5) has hardware which sends and detects all of the necessary signals for FAX communication and
DTMF.
It can be controlled by writing commands from the ASIC (IC1) to the register in the modem (IC5).
This modem (IC5) also sends DTMF signals, and detects busy tones, dial tones and DTMF.
Overview of Facsimile Communication Procedures (ITU-T Recommendation):
1. ON ITU-T (International Telecommunications´ Union.)
The No. XIV Group of ITU-T, one of the four permanent organizations of the International Telecommunications Uniib (ITU),
investigates and make recommendations on international standards for facsimiles.
investigates and make recommendations on international standards for facsimiles.
2. Definition of Each Group
·
Group I (G1)
A-4 size documents without using formats which reduce the band width of a signal sent over telephone lines.
Determined in 1968.
Determined in 1968.
Transmission for about 6 minutes at scanning line density of 3.85 lines/mm.
·
Group II (G2)
Using reduction technology in the modulation/demodulation format, an A-4 size document is sent at an official scanning line
density of 3.85 lines/mm for about 3 minutes.
Methods to suppress redundancy are not used.
Determined in 1976.
density of 3.85 lines/mm for about 3 minutes.
Methods to suppress redundancy are not used.
Determined in 1976.
·
Group III (G3)
A method of suppressing redundancy in the image signal prior to modulation is used. An A-4 size document is sent with
about one minute.
about one minute.
Determined in 1980.
·
Group IV (G4)
Transmission is via the data network. A method is provided for suppressing redundancy in signals prior to transmission, and
error-free reception of transmission is possible.
The scope of these facsimile applications is not limited simply to transmission of written statements. Through symbiotic
linkages with other communication methods, it can be expected to expand to include integrated services.
error-free reception of transmission is possible.
The scope of these facsimile applications is not limited simply to transmission of written statements. Through symbiotic
linkages with other communication methods, it can be expected to expand to include integrated services.
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3. Facsimile Call Time Series
As shown in the following diagram, the facsimile call time series is divided into five phases.
Phase A : Call setting
Call setting can be manual/automatic.
Phase B : Pre-message procedure
Phase B is a pre-processing procedure and sequence for confirming the status of the terminal, transmission route, etc. and for
terminal control. It implements the terminal preparation status, determines and displays terminal constants, confirms
synchronization status, etc. and prepares for transmission of facsimile messages.
terminal control. It implements the terminal preparation status, determines and displays terminal constants, confirms
synchronization status, etc. and prepares for transmission of facsimile messages.
Phase C : Message transmission
Phase C is the procedure for transmitting facsimile messages.
Phase D : Post message procedure
Phase D is the procedure for confirming that the message is completed and received. For continuous transmission, phase B
or phase C are repeated for transmission.
or phase C are repeated for transmission.
Phase E : Call retrieval
Phase E is the procedure for call retrieval, that is for circuit disconnection.
4. Concerning Transmission Time
Transmission Time
= Control Time
+ Image Transmission Time
+ Hold Time
Transmission time consists of the following.
Control time:
This is time at the start of transmission when the functions at the sending and receiving sides are confirmed, the
transmission mode is established, and transmission and reception are synchronized.
transmission mode is established, and transmission and reception are synchronized.
Image transmission time:
This is the time required for the transmission of document contents (image data). In general, this time is recorded in the
catalog, etc.
catalog, etc.
Hold time:
This is the time required after the document contents have been sent to confirm that the document was in fact sent, and to
check for telephone reservations and/or the existence of continuous transmission.
check for telephone reservations and/or the existence of continuous transmission.
5. Facsimile Standards
Item
Telephone Network Facsimile
G3 Machine
Connection Control Mode
Telephone Network Signal Mode
Terminal Control Mode
T. 30 Binary
Facsimile Signal Format
Digital
Modulation Mode
PSK (V. 27 ter) or QAM (V. 29)
Transmission Speed
300 bps (Control Signal)
2400, 4800, 7200, 9600 bps (FAX Signal)
2400, 4800, 7200, 9600 bps (FAX Signal)
Redundancy Compression
Process
(Coding Mode)
Process
(Coding Mode)
1 dimension: MH Mode
2 dimension: MR Mode (K=2.4)
2 dimension: MR Mode (K=2.4)
Resolution
Main Scan: 8 pel/mm
Sub Scan: 3.85, 7.7l/mm
Sub Scan: 3.85, 7.7l/mm
Line Synchronization Signal
EOL Signal
1 Line Transmission Time
[ms/line]
[ms/line]
Depends on the degree of data reduction.
Minimum Value: 10, 20
Can be recognized in 40ms.
Minimum Value: 10, 20
Can be recognized in 40ms.
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6. Explanation of Technology
a. G3 Communication Signals (T. 30 Binary Process)
For G3 facsimile communication, this is the procedure for exchanging control signals between the sending and receiving
machines both before and after transmission of image signals.
Control signals at 300 bps FSK are: 1850 Hz...0, 1650Hz...1.
An example of the binary process in G3 communication is shown below.
machines both before and after transmission of image signals.
Control signals at 300 bps FSK are: 1850 Hz...0, 1650Hz...1.
An example of the binary process in G3 communication is shown below.
Explanation of Signals
Control signals are comprised mainly of 8-bit identification signals and of the data signals added to them. Data signals are
added to DIS and DCS signals.
added to DIS and DCS signals.
Signal.....DIS (Digital Identification Signal)
Identification Signal Format.....00000001
Identification Signal Format.....00000001
Function:
Notifies the capacity of the receiving unit. The added data signals are as follows.
Notifies the capacity of the receiving unit. The added data signals are as follows.
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(Example)
Bit No.
DIS/DTC
DCS
1
Transmitter - T.2 operation
2
Receiver - T.2 operation
Receiver - T.2 operation
3
T.2 IOC = 176
T.2 IOC = 176
4
Transmitter - T.3 operation
5
Receiver - T.3 operation
Receiver - T.3 operation
6
Reserved for future T.3 operation features.
7
Reserved for future T.3 operation features.
8
Reserved for future T.3 operation features.
9
Transmitter - T.4 operation
10
Receiver - T.4 operation
Receiver - T.4 operation
11, 12
(0, 0)
(0, 1)
(1, 0)
(1, 1)
(0, 1)
(1, 0)
(1, 1)
Data signaling rate
V.27 ter fall back mode
V.27 ter
V.29
V.27 ter and V.29
V.27 ter fall back mode
V.27 ter
V.29
V.27 ter and V.29
Data signaling rate
2400 bit/s, V.27 ter
4800 bit/s, V.27 ter
9600 bit/s, V.29
7200 bit/s, V.29
2400 bit/s, V.27 ter
4800 bit/s, V.27 ter
9600 bit/s, V.29
7200 bit/s, V.29
13
Reserved for the new modulation system.
14
Reserved for the new modulation system.
15
Vertical resolution = 7.7 line/mm
Vertical resolution = 7.7 line/mm
16
Two-dimensional coding capability
Two-dimensional coding
17, 18
(0, 0)
(0, 1)
(1, 0)
(1, 1)
Recording width capabilities
1728 picture elements along scan line length of
215 mm ± 1%
1728 picture elements along scan line length of
215 mm ± 1% and
2048 picture elements along scan line length of
255 mm ± 1% and
2432 picture elements along scan line length of
303 mm ± 1%
1728 picture elements along scan line length of
215 mm ± 1% and
2048 picture elements along scan line length of
255 mm ± 1%
Invalid
1728 picture elements along scan line length of
215 mm ± 1%
1728 picture elements along scan line length of
215 mm ± 1% and
2048 picture elements along scan line length of
255 mm ± 1% and
2432 picture elements along scan line length of
303 mm ± 1%
1728 picture elements along scan line length of
215 mm ± 1% and
2048 picture elements along scan line length of
255 mm ± 1%
Invalid
Recording width
1728 picture elements along scan line length of
215 mm ± 1%
2432 picture elements along scan line length of
303 mm ± 1%
1728 picture elements along scan line length of
215 mm ± 1%
2432 picture elements along scan line length of
303 mm ± 1%
2048 picture elements along scan line length of
255 mm ± 1%
255 mm ± 1%
Invalid
19, 20
(0, 0)
(0, 1)
(1, 0)
(1, 1)
(0, 1)
(1, 0)
(1, 1)
Maximum recording length capability
A4 (297 mm)
Unlimited
A4 (297 mm) and B4 (364 mm)
Invalid
A4 (297 mm)
Unlimited
A4 (297 mm) and B4 (364 mm)
Invalid
Maximum recording length
A4 (297 mm)
Unlimited
B4 (364 mm)
Invalid
A4 (297 mm)
Unlimited
B4 (364 mm)
Invalid
Signal.....DCS (Digital Command Signal)
Identification Signal Format.....X1000001
Identification Signal Format.....X1000001
Function:
Notifies the capacity of the receiving machine obtained at DIS and announces the transmission mode of the sender. The added
data signals are as follows.
Notifies the capacity of the receiving machine obtained at DIS and announces the transmission mode of the sender. The added
data signals are as follows.
(Example)
Bit No.
DIS/DTC
Standard setting
DCS
21, 22, 23
(0, 0, 0)
(0, 0, 1)
(0, 1, 0)
(1, 0, 0)
(0, 1, 1)
(1, 1, 0)
(1, 0, 1)
(1, 1, 1)
(0, 0, 1)
(0, 1, 0)
(1, 0, 0)
(0, 1, 1)
(1, 1, 0)
(1, 0, 1)
(1, 1, 1)
Minimum scan line time capability of the receiver
20 ms at 3.85 l/mm: T7.7 = T3.85
40 ms at 3.85 l/mm: T7.7 = T3.85
10 ms at 3.85 l/mm: T7.7 = T3.85
5 ms at 3.85 l/mm: T7.7 = T3.85
10 ms at 3.85 l/mm: T7.7 = 1/2 T3.85
20 ms at 3.85 l/mm: T7.7 = 1/2 T3.85
40 ms at 3.85 l/mm: T7.7 = 1/2 T3.85
0 ms at 3.85 l/mm: T7.7 = T3.85
20 ms at 3.85 l/mm: T7.7 = T3.85
40 ms at 3.85 l/mm: T7.7 = T3.85
10 ms at 3.85 l/mm: T7.7 = T3.85
5 ms at 3.85 l/mm: T7.7 = T3.85
10 ms at 3.85 l/mm: T7.7 = 1/2 T3.85
20 ms at 3.85 l/mm: T7.7 = 1/2 T3.85
40 ms at 3.85 l/mm: T7.7 = 1/2 T3.85
0 ms at 3.85 l/mm: T7.7 = T3.85
Minimum scan line time
20 ms
40 ms
10 ms
5 ms
20 ms
40 ms
10 ms
5 ms
0 ms
24
Extend field
1
Extend field
25
2400 bit/s handshaking
0
2400 bit/s handshaking
26
Uncompressed mode
0
Uncompressed mode
27
Error correction mode
0
Error correction mode
28
Set to "0".
0
Frame size 0 = 256 octets 1 = 64 octets
29
Error limiting mode
0
Error limiting mode
30
Reserved for G4 capability on PSTN
0
Reserved for G4 capability on PSTN
31
Unassigned
0
32
Extend field
1
Extend field
33
(0)
(1)
(1)
Validity of bits 17, 18
Bits 17, 18 are valid
Bits 17, 18 are invalid
Bits 17, 18 are valid
Bits 17, 18 are invalid
0
Recording width
Recording width indicated by bits 17, 18
Recording width indicated by this field bit
information
Recording width indicated by bits 17, 18
Recording width indicated by this field bit
information
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KX-FT78RU-B / KX-FT78RU-W
