Mitsubishi MELSEC L Series User Manual page 104

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REMARKS
The overview of the RS · CS controls are described.
(1) When transmission data
1) The Q series C24 detects the modem/TA data reception capability
from on/off of the CS (CTS) signal.
2) When the CS (CTS) signal is on, data transmission from the Q
series C24 starts or continues.
When the CS (CTS) signal is off, data transmission from the Q
series C24 is interrupted.
(2) When reception data
1) The Q series C24 side reception capability is notified to the
modem/TA by the on/off of the RS (RTS) signal.
2) When the RS (RTS) signal is on, the Q series C24 can receive data.
Start/continue data transmission from the modem/TA to the Q series
C24.
When the RS (RTS) signal is off, the Q series C24 cannot receive
data. Cancel data transmission from the modem/TA to the Q series
C24.
3) The on/off of the RS (RTS) signal is controlled by the following
conditions of the Q series C24:
• ON
Performed when the OS area for reception data storage in the Q
series C24 becomes 64 bytes (default) or less.
• OFF
Performed when the OS area for reception data storage in the Q
series C24 becomes 263 bytes (default) or more.
(l) Modem function error code storage area (address 545 (221
1) Stores the error code when an error occurs during the modem function
or abnormal signal (such as the initialization/connection abnormal
completion signal X13) turns on.
2) Refer to the User's Manual (Basic) for the error codes.
(m) Modem function sequence status storage area (address 546 (222
1) The current status during use of the modem function is stored as a
number.
2) See Section 3.4.1 for storage values for the modem function sequence
status when using the modem.
3 COMMUNICATIONS BY THE MODEM FUNCTION
OFF control of the RS (RTS) signal
ON control of the RS (RTS) signal
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