Mitsubishi MELSEC L Series User Manual page 76

(6) Connectable lines
(7) Communication system
(8) Data communication and notification to external devices
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1) The connections can be made with the following lines.
Perform connection tests beforehand and confirm that connection is possible.
• Public line or office telephone system of analog two-line method
• Digital line (ISDN)
2) It is not possible to connect to call-waiting lines, in order to avoid data errors
or automatic line disconnection due to the call-waiting interrupt tone.
3) Avoid connections with party-line telephones to avoid interrupted calls during
communication.
4) If an alert sound is sent at fixed intervals from the communication machine to
prevent long-term calls, data may experience errors.
It is recommended to check the normality/abnormality of data reception
between devices, and perform transmission-retry processing when an
abnormality is detected.
5) See the modem/TA manual regarding the connection from a modem to public
line/office telephone system, or from a TA (terminal adapter) to a digital line.
Communication via the modem function is performed using full-duplex
communication.
Connections cannot be made devices designed for half-duplex communication.
1) Data communication with external devices and notification to a pager receiver
are performed using the public line or electric wave transmitted from the
electric wave transmission base.
There might occur a condition in which correct data communication or
notification cannot be carried out due to an error from the system's setup
environment, electric-wave transmission status, error in the partner device,
etc.
Perform a connection test beforehand, and confirm that connection is
possible.
2) In notification processing via electric-wave transmission, errors from the
pager receiver cannot be detected.
Setup a separate call circuit with a lamp display or buzzer to ensure the
safety of the programmable controller system.
3 COMMUNICATIONS BY THE MODEM FUNCTION
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