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First confirm whether the recording paper is installed properly or not before starting troubleshooting. (Refer to "Remarks".)

• "596: Transmit level set" represents a service code. (Refer to Service Function Table (P.67).)
• #06 : Refer to for Program Mode Table (P.104) Fax ring count.

Regarding the reception problem, we have investigated the conceivable causes in the flow chart except for the software-related
errors. However, some troubles may occur due to the software-related problems such as "OUT OF PAPER" when the fax
switches to the memory receiving mode and the memory capacity becomes full of the unprintable data. In this case, error mes-
sages [MEMORY FULL] and its main cause, for example "CHECK PAPER" are displayed on the LCD. Once you solve the main
problem, [MEMORY FULL] will be cancelled and the reception problem will be resolved.
LCD display messages indicating the error causes are shown below.
CHECK PAPER
COVER OPEN
UNIT OVERHEATED (COVER OPEN, etc.)...Reset the unit.
PAPER JAMMED
CHECK FILM
Please refer to Error Messages-Display (P.78) for the above items. If it turns out to be a hardware deformity, please check
each sensor. (Refer to Test Mode (P.63).)

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(*1): Test Mode (P.63)
(*2): Analog Board Section (P.129)

99

The following two causes can be considered for this symptom.
Cause 1:

The other party is executing automatic dialing, the call has been received by this unit, and the CED or DIS signal response time
is too long. (In most cases, this unit detects the CNG signal and can respond to CED or DIS.) (According to the ITU-T standard,
the communication procedure is cancelled when there is no response from the other party within 35 sec, so that the other party
releases the line.)

As shown in the chart above, the total handshaking time must be reduced, but because of the long distance connection and link-
ing of several stations, the line connection time cannot be reduced. Accordingly, the following countermeasures should be tried.
(A)... As the 35 sec. count is started directly after dialing or directly after the START button has been pressed for models with a
START button, the other party should be called manually, if possible. Another possibility is entering two pauses at the end of the
auto dial number on the transmission side. Then the count start time can be delayed for 2 pauses (about 10 sec.).

Erroneous detection because of an echo or an echo canceler.

The signal from FAX1 reaches FAX2 via stations 1 and 2, but the reflection signal at station 2 also returns via station 1 (echo).
As the distance between station 1 and station 2 is far, the echo returns to FAX 1 at a max of 600 msec after transmission. There
is a possibility that this signal is detected erroneously as the signal from FAX2. For a normal call, there is also a possibility that
the echo of their own voice will make the call difficult to understand. For this reason, each station (station 1 and station 2)
attaches echo cancelers (S1 and S2) for international lines or long distance lines. For the echo canceler, the level of the trans-
mission signal from FAX 1 is compared with the level of the reception signal from FAX2. When the transmission signal is larger,
S1 is closed while S2 is opened when it is smaller. In other words, for transmission from FAX1, S1 is closed and S2 is open, so
that the echo does not return to FAX1.

100

Fig. a 

(Overlapping the Echo of the DIS signal and DCS signal)

Fig. b 

(Countermeasure by Changing the CED Frequency)

No. Countermeasure Side

Echo Communication Problem Example

Countermeasure

Service Code

1

Sending side

Some time is needed to compare the level 
of the receiving and sending signals for the 
echo canceler. The header of the training 
signal lacks due to a switching delay to 
close S1.

Add a dummy signal to the beginning of 
the training signal.

Service code (521)
(International mode select)
This countermeasure becomes 
the default value.

2

Receiving side

The echo canceler function stops accord-
ing to a CED signal frequency of 2100Hz 
(S1 and S2 are both ON), a DIS signal is 
returned as an echo, and a DCS signal 
from the sending side overlaps the DIS 
echo. Then the receiving side FAX cannot 
retrieve the DCS signal.
(Refer to Fig. a)

Change to a 1100Hz CED signal fre-
quency. (Refer to Fig. b)

Service code (520)
(CED frequency select)

Receiving side

Change the regular rime of 75 msec 
between the CED signal and DIS signal 
to 500 msec. This will give at least 250 
msec to recover the echo canceler 
operation. (Refer to Fig. c)

Service code (593)
 (Time between CED and 300 
bps)

Sending side

The sending side FAX sends a DCS 
signal not after receiving the 1st DIS 
signal but after receiving the 2nd DIS 
signal. (Refer to Fig. d) 

Service code (594)
 (Overseas DIS detection 
select)

3

Sending side

Communication failure occurs in a long dis-
tance communication on the telephone line 
without an echo canceler.

or

There are some cases (e.g. Mobil comms.) 
which cause the collision of TX / RX signals 
due to the delay / echo and noise of the 
network / terminal. (Refer to Fig. e)

Decrease the transmission level from -
10 dBm to -15 dBm and the echo level 
will decrease.

Service code (596)
 (Transmit level set)

4

Sending side
Receiving side

Decrease the receiving sensitivity from 
-13 dBm to about -32 dBm so an echo 
signal will not received.

Service code (598)
 (Receiving sensitivity)

5

Sending side
Receiving side

Set additional Pause time (Service 
mode: code No. 774) in between the 
original and its repeated signals, to pre-
vent the collision of the signals at both 
end.

Service code (774)
 (T4 timer)