Computer 5V or 0V output to Sensaphone Express II

[JordanL]

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I'm using a LabView controlled alarm system in my lab where an alarm condition triggers a USB DAQ analog output signal to switch from +5V to 0V. This signal is going to a sensaphone express II alarm box normally open relay input. The normally open relay input sees 5V as an open (no alarm condition) and 0V as a short (alarm). My problem is the my USB DAQ only has 5 analog output and I would like to have more. I don't want to spend a lot of money. Any suggestions on an inexpensive USB DAQ or PCI DAQ with similar functionality but more channels? Or better yet a way to get a similar effect straight out of the computer? Maybe USB? RS232?

[Dennis_Knutson]

What DAQ card are you using? It doesn't have any digital outputs?

USB or RS232 won't do you any good. You could use the parallel port.

[JordanL]

I'm using an iotech personal daq 3000 series.  It does have digital outputs.  The problem with the digital outputs is when I set the output to 0V and expect to see a short between the digital output channel and ground I see something like 400 ohms. 

[AnalogKid2DigitalMan]

Set your meter to volts, not ohms. I bet they are TTL outputs, not contact closure outputs.I'm not about to register at MCC's site to download the data sheeeet.

-AK2DM

[Dennis_Knutson]

Instead of driving the sensors with analog or digital signals, you could drive relays and have actual shorts and opens instead of some active circuit.

[JordanL]

I guess I could drive relays with the outputs.  I was hoping to end up with less hardware instead of more.  Something really simple.