User guide

UC864-E/G/WD/WDU Hardware User Guide
1vv0300766a Rev.4
- 03/02/09
Reproduction forbidden without Telit Communications S.p.A’s. written authorization - All Rights Reserved. Page 40 of 78
The signals of the UC864-E/G/WD/WDU serial port are:
RS232
Pin
Number
Signal
UC864-
E/G/WD/WDU
Pad Number
Name
Internal
Pulls
(On Chip)
Usage
1
DCD -
dcd_uart
32
Data Carrier
Detect
Pull-Up
Output from the UC864-E/G/WD/WDU that
indicates the carrier presence
2
RXD -
Tx_uart
26
Transmit line *see
Note
Pull-Up
Output transmit line of UC864-E/G/WD/WDU
UART
3
TXD -
Rx_uart
25
Receive line *see
Note
Pull-Down
Input receive of the UC864-E/G/WD/WDU
UART
4
DTR -
dtr_uart
29
Data Terminal
Ready
Pull-Up
Input to the UC864-E/G/WD/WDU that
controls the DTE READY condition
5 GND 5,6,7 Ground - ground
6
DSR -
dsr_uart
27 Data Set Ready Pull-Down
Output from the UC864-E/G/WD/WDU that
indicates the module is ready
7
RTS -
rts_uart
31 Request to Send Pull-Down
Input to the UC864-E/G/WD/WDU that
controls the Hardware flow control
8
CTS -
cts_uart
28 Clear to Send Pull-Up
Output from the UC864-E/G/WD/WDU that
controls the Hardware flow control
9
RI -
ri_uart
30 Ring Indicator Pull-Up
Output from the UC864-E/G/WD/WDU that
indicates the Incoming call condition
NOTE:
According to V.24, RX/TX signal names are referred to the application side, therefore
on the UC864-E/G/WD/WDU side these signal are on the opposite direction: TXD on
the application side will be connected to the receive line (here named TXD/ rx_uart )
of the UC864-E/G/WD/WDU serial port and vice versa for RX.
TIP:
For minimum implementation, only the TXD and RXD lines can be connected, the
other lines can be left open provided a software flow control is implemented.