big john
Senior Member
- Location
- Portland, ME
We've got some telemetry that takes place over 2-pair dry DSL lines.
I've been working with the phone company to verify operation and ran into something I don't understand:
They can inject a 1004Hz signal using a tester made by Tempo that reads the loop loss in dBm. When I connect a DMM to their tester, I can read that it's putting out 1004Hz at about 1.5 volts.
When I go to the other end of the DSL line, I can hear this tone with a butt-set and see it on my DMM.
Now, I've tried to reproduce this test myself: I connect a function generator to the line at 1004Hz and go to the other end, I can hear the tone with the butt-set but there's not a meter in my arsenal capable of picking up the frequency, even if I inject it as high as 10 volts.
Why on earth would I not be able to reproduce this test?
-John
I've been working with the phone company to verify operation and ran into something I don't understand:
They can inject a 1004Hz signal using a tester made by Tempo that reads the loop loss in dBm. When I connect a DMM to their tester, I can read that it's putting out 1004Hz at about 1.5 volts.
When I go to the other end of the DSL line, I can hear this tone with a butt-set and see it on my DMM.
Now, I've tried to reproduce this test myself: I connect a function generator to the line at 1004Hz and go to the other end, I can hear the tone with the butt-set but there's not a meter in my arsenal capable of picking up the frequency, even if I inject it as high as 10 volts.
Why on earth would I not be able to reproduce this test?
-John