41110590
Rev 6.1
January 28, 2019
22
Product Technical Specification and
User Guide
Interfaces/Peripherals
The RS232 interface has been designed to allow flexibility in the use of the serial interface signals.
However, the use of TX and RX signals are mandatory; while the use of CTS, RTS, and DTR signals
are optional.
Note:
The modem is designed to operate with Hardware Flow Control. It is recommended to use RS232-
RTS and RS232-CTS for hardware flow control to avoid data corruption during transmission.
The modem also implements the Serial Port Shutdown feature with the DTR signal. It is
recommended to use RS232-DTR signal to benefit from the current consumption improvement
performed by this feature. For more information about the Serial Port Shutdown, refer to section
7.2.2 Serial Port Shutdown Mode.
2.2.1.2.2.
4-wire Serial Interface Hardware Design
The signals used in this interface hardware design are as follows:
•
RS232-TXD
•
RS232-RXD
•
RS232-CTS
•
RS232-RTS
Modem
(DCE)
DTE
RS232-TXD
GND
RS232-RXD
RS232-RTS
7
3
8
4
TX
RX
RTS
CTS
RS232-CTS
Figure 8.
4-wire Serial Link Implementation
2.2.1.2.3.
2-wire Serial Interface Hardware Design
The signals used in this interface hardware design are as follows:
•
RS232-TXD
•
RS232-RXD
Note:
Although this case is possible, it is not recommended.
The flow control mechanism must be managed from the customer end.
Modem
(DCE)
DTE
RS232-TXD
GND
RS232-RXD
7
3
TX
RX
Figure 9.
2-wire Serial Link Implementation
