Sierra Wireless airprime wismo218 ユーザーズマニュアル
WA_DEV_W218_PTS_002
Rev 005
Page 42 of 109
Product Technical Specification &
Customer Design Guidelines
Customer application
( DTE )
WISMO218
( DCE )
ON/~OFF
CT103/TXD
CT104/RXD
~CT105/RTS
~CT106/CTS
37
39
40
38
GND
Rx
RTS
CTS
GND
Tx
41
42
~CT107/DSR
44
~CT108/DTR
~CT109/DCD
~CT125/RI
45
43
DCD
RI
DSR
DTR
Figure 10. Example of V24/CMOS Serial Link Implementation for 5-wire UART
The designs shown in Figure 8, Figure 9, and Figure 10 are basic designs. Both the DCD and RI can be
left open when not used.
left open when not used.
However, a more flexible design to access this serial link with all modem signals is shown below.
Customer application
( DTE )
WISMO218
( DCE )
GND
ON/~OFF
~CT107/DSR
~CT109/DCD
~CT108/DTR
~CT125/RI
37
43
44
45
42
GND
DCD
DTR
RI
GND
DSR
CT103/TXD
CT104/RXD
~CT105/RTS
~CT106/CTS
41
39
40
38
Rx
RTS
RTS
CTS
Tx
2x 10K
2.8Volt
Figure 11. Example of Full Modem V24/CMOS Serial Link Implementation for full-UART
There is an internal 10K pull-up resistor on RI and DCD to set it to HIGH level during the reset
state.
state.
The UART interface is a 2.8V type, but is 3V tolerant.