80-001114
SysLINK Hardware Manual
Page 14
DB-25
Pin
Number
RS-232
Name
Direction
Signal Function
2
TX
I
Serial data in, from remote device to SysLINK
3
RX
O
Serial data out, from SysLINK to remote device
4
RTS
I
Flow control, to enable SysLINK to send data
5
CTS
O
Flow control, to enable remote device to send data
6
DSR
O
Signals remote device that the SysLINK is attached
and powered on
7
GND
Signal ground
8
DCD
O
Signals remote device that SysLINK has a valid
connection
20
DTR
I
Signals SysLINK that the remote device is attached
and powered on
22
RI
O
Ring Indicator
Table 2-1: EIA-232 DB-25 DCE Pinouts
Figure 2-2 shows a cable to connect most devices to the SysLINK.
DB-25 Pin (DCE)
Number/Signal
DB-25 Pin (DTE)
Number/Signal
2 TX
22 RI
20 DTR
8 DCD
7 GND
6 DSR
5 CTS
4 RTS
3 RX
2 TX
22 RI
20 DTR
8 DCD
7 GND
6 DSR
5 CTS
4 RTS
3 RX
Figure 2-2: DB-25 to DB-25 Full Cable
The SysLINK does not require the use of all 9 wires. Only the RX, TX, and GND signals are
essential. DTR/DSR and RTS/CTS are only necessary for flow control. DCD is used to
indicate a connection and RI is only required for connections that need a ring indicator.
