UPI and memoexpress?

EKS · Post by **EKS** » Tue Apr 02, 2002 8:04 pm

I've built the scaled down version of the UPI, and am having a hard time getting it to read a memoexpress pager.

When a scope is put on the pagers tx and rx pins, it shows about 2 volts, and the TTL pulses are going to ground. I can't get the pps to read the pager, but just before it times out the pagers display shows "6 222222222222" and then it does a reset. (well the display blanks for a second and then the time goes back to 12:00)

Is a pull-up or pull down resistor required on the datalines to get a 5v signal, or do I just have to invert the signal?

I also tried moving connecting pin 13 of the lm339 directly to pin 11 on the max232 rather than having it jumped to pin 5 on the lm339. The signal was a little cleaner on both ends, but it didn't help.

Thanks for any advice you might have as well as the past few months of reading.

EKS · Post by **EKS** » Tue Apr 02, 2002 9:20 pm

Nevermind. Figured it out. Pin 5 and 13 on the 339 shouldn't be connected together as in the schematic.

EMS Geek · Post by **EMS Geek** » Thu Apr 04, 2002 3:47 am

Hi,
Do you have a UPI that you can sell or do build any?

I have been trying for a month to reprogram an Advisor Gold without success. I have tried three different interfaces and nothing.

Thanks, Eric ([email protected])