Electronics question

["Paul Gordon" <paul_gordon@xxxxxxxxxxx>]

One for the electronics guru's here perhaps?

I run a couple of the Quasar temp monitoring boards into my HA server. I've
just been trying to move them over to the new Avocent serial-over-IP box
that has replaced my old 8-port PCI RS232 card. - these are among the last
couple of devices to reconnect, I've already successfully configured 2
Comfort UCM's and a CurrentCost...

I'm not getting any data from the 3145's though, and I'm wondering if its
related to their use of power from the DTR line of the connected serial
port? Here's the circuit diagram:
http://www.quasarelectronics.com/images/electronic-kit/3145schematic.gif

I've put a meter across the DTR & GND pins on the RJ45 outlet jacks on
the
Avocent box, and I'm seeing 3.5VDC. I've also put the meter across a couple
of points in the 3145 board itself, and I'm seeing voltages at various
points, - for instance, there is 0.99VDC at the DS1820 signal & GND
connection points, so there appears to be power to the circuit, - but my
question is, is it enough? - I've not yet tried to test the output from the
PC serial port it was previously attached to, - it's not easy to do without
butchering a serial cable, so I can't compare them. However, the Quasar
page
for these circuits does mention the possibility of data errors due to
unstable power from the DTR pin...

I'm emailing the question directly to Quasar as well, but while I'm waiting
for their reply, I'd appreciate any thoughts anyone else might have...

TIA

Paul G...





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