Sierra Wireless WISMO218 - Manual (Page 38)

WA_DEV_W218_PTS_002 Rev 005 Page 38 of 109
Product Technical Specification &
Customer Design Guidelines
Main Serial Link (UART)
A flexible 8-wire serial interface is available on the WISMO218 that complies with the V24 protocol
signaling, but not with the V28 (electrical interface) due to its 2.8-Volt interface.
Features
The supported baud rates of the UART are 1200, 2400, 4800, 9600, 19200, 38400, 57600 and 115200
Kbits, with autobauding.
The signals used by the UART are as follows:

TX data (CT103/TXD)

RX data (CT104/RXD)

Request To Send (~CT105/RTS)

Clear To Send (~CT106/CTS)

Data Terminal Ready (~CT108/DTR)

Data Set Ready (~CT107/DSR)

Data Carrier Detect (~CT109/DCD)

Ring Indicator (~CT125/RI)
Pin Description
Table 7. Main Serial Link Pin Descriptions
* According to PC (DTE) view
The rising time and falling time of the reception signals (mainly CT103/TXD) have to be less than
300ns.
Tip: The WISMO218 is designed to operate using all the serial interface signals. In particular, it is
recommended to use ~CT105/RTS and ~CT106/CTS for hardware flow control in order to avoid data
corruption during transmissions.
Signal Pin Number I/O
I/O
Type
Reset
State
Description
CT103/TXD* 38 I 2V8 1 Transmit serial data
CT104/RXD* 40 O 2V8 1 Receive serial data
~CT105/RTS* 39 I 2V8 0 Request To Send
~CT106/CTS* 41 O 2V8 0 Clear To Send
~CT107/DSR* 42 O 2V8 1 Data Set Ready
~CT108/DTR* 44 I 2V8 1 Data Terminal Ready
~CT109/DCD* 43 O 2V8 1 Data Carrier Detect
~CT125/RI * 45 O 2V8 1 Ring Indicator
GND* GND Ground