Hello Frank,
The RTSI lines on the 1408 are used for triggering other National Instruments boards without using the PCI bus (introducing a software latency).
The 1408 has 4 trigger lines (0 - 3) that are accessible from the 25 pin D sub.
- See the IMAQ 1408 User Manual for a pinout.
- National Instruments offers a cable to breakout the 25 pins (IMAQ 2514 will breakout to 14 BNC connectors).
- See http://sine.ni.com/apps/we/nioc.vp?lang=US&pc=mn&cid=1289 for a complete selection of cables.