Network Card - Network Interface Controller (NIC) User Manual
Chapter 3 Signal Connections
NI PCI-8254R User Manual 3-6 ni.com
16 2 TTL Input 1 Pulse generator 
trigger input
Trigger Change 
Detector, 
General-purpose 
input
17 3 C Common-mode 
signal of the 
NI 8254R main 
power
—
18 20 TTL Output 4 Pulse generator 
output
General-purpose 
output
19 21 TTL Output 5 General-purpose 
output
—
20 22 C Common-mode 
signal of the 
NI 8254R main 
power
—
21 23 TTL Output 6 General-purpose 
output
—
22 24 TTL Output 7 General-purpose 
output
—
23 22 C Common-mode 
signal of the 
NI 8254R main 
power
—
24 NC TRIG 1
*
/TTL 
Output 9
Pulse generator 
output
General-purpose 
output
25 33 V
iso
Isolated power —
26 34 C
iso
Isolated 
common-mode 
signal
—
Table 3-3. Signal Connections (Continued)
44-Pin D-SUB 
on NI 8254R 
Pin Number
37-Pin Terminal 
Block Number
Signal Name
Primary 
Function
Alternate 
Function










