27: MODEM MODE
27-14 « FC4A MICROSMART USER’S MANUAL »
Troubleshooting in Modem Communication
When a start internal relay is turned on, the data of D8111 (modem mode status) changes, but the modem does
not work.
Cause: A wrong cable is used or wiring is incorrect.
Solution: Use the modem cable 1C (FC2A-KM1C).
The DTR or ER indicator on the modem does not turn on.
Cause: A wrong cable is used or wiring is incorrect.
Solution: Use the modem cable 1C (FC2A-KM1C).
When a start internal relay is turned on, the data of D8111 (modem mode status) does not change.
Cause: Modem protocol is not selected for port 2.
Solution: Select Modem Protocol for Port 2 using WindLDR (Configure > Function Area Settings > Communica-
tion) and download the user program to the CPU module.
When an initialization string is sent, a failure occurs, but sending ATZ completes successfully.
Cause: The initialization string is not valid for the modem.
Solution: Refer to the user’s manual for the modem and correct the initialization string.
When a dial command is sent, a result code “NO DIALTONE” is returned and the telephone line is not connected.
Cause 1: The modular cable is not connected.
Solution 1: Connect the modular cable to the modem.
Cause 2: The modem is used in a PBX environment.
Solution 2: Add X0 or X3 to the initialization string stored in data registers D8145-D8169, and try initialization again.
Dialing completes successfully, but the telephone line is disconnected in a short period of time.
Cause 1: The modem settings at the both ends of the line are different.
Solution 1: Make the same settings for the modems at the both ends.
Cause 2: The model of the modems at the both ends of the line is different.
Solution 2: Use the same modems at the both ends.
Cause 3: The quality of the telephone line is low.
Solution 3: Decrease the baud rate of the MicroSmart to lower than 9600 bps.
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