• Code: 436
• Description: DCN received after transmitting FTT.
• Causes: Transmitter is defective or incompatible. Line quality is poor.

• Code: 456
• Description: Received relay transfer request or confidential document to distribute to an end receiving station or all confidential mailboxes are used.
• Causes:

• Code: 490
• Description: Sum of error lines exceeded the limit (Function Parameter No. 70) of 64 lines.
• Causes: Line quality is poor. MAIN PCB is defective.

• Code: 494
• Description: Interval between two EOLs was more than 10 sec. when receiver received message data.
• Causes: Transmitter is defective. Line quality is poor. (EOL is damaged due to line noise) MAIN PCB is defective.

• Code: 495
• Description: During reception, CD turned OFF or continued ON for long time. During communication, lost loop - current.
• Causes: Line is disconnected. Transmitter is defective. MAIN PCB is defective.

• Code: 501
• Description: Remote unit does not have compatible Modem.
• Causes:

• Code: 502
• Description: During reception, CD turned OFF or continued ON for long time. During communication, lost loop - current.
• Causes: Line is disconnected. Transmitter is defective. MAIN PCB is defective.

• Code: 503
• Description: CS of modem is not able to turn ON during training.
• Causes: MAIN PCB is defective. Line is disconnected.