Impedance for Taiwanese Telco's

Life Technology
1

I am trying to get my brand new Sipura SPA-3000 to receive DTMF signals here in Taiwan. Everything else seems to be working just fine, I can make calls via landline or VoIP, I can receive calls from either line, it even translates the CallerID properly for my European phone. What I am having trouble with, is when I call the SPA from the landline, it picks up the call, and waits for me to enter a PIN. When I enter the PIN, it does not recognize it properly, and I am unable to log in. Some guy on voxilla.com seems to think it is an impedance mismatch, and that I would have to set the impedance on the device properly. Anybody knows what the impedance should be?

Any help is appreciated.

2

it is something you can measure on the line with a multi-meter?

3

Impedance is usually frequency dependent. So just sticking a multi-meter into the phone jack might not do the trick. I am affraid you need some more sophisticated device.

In this case it seems to be a matter of how the SPA-3000 “measures” the signals coming through the line. I will just go ahead and test all possible impedance settings (about 10) and see which one works.

But I am affraid that the correct settings might be more complicated than that.

4

What are the possible impedance settings?

Analog landlines have a typically impedance of 600 Ohm while digital lines (E1, ISDN etc.) typically have 120 Ohm.

5

[quote=“Rascal”]What are the possible impedance settings?

Analog landlines have a typically impedance of 600 Ohm while digital lines (E1, ISDN etc.) typically have 120 Ohm.[/quote]

I did set it to 600 Ohm, but that does not work, here is the full list.

600
900
270+750||150nF
220+820||120nF
370+620||310nF
320+1050||230nF
370+820||110nF
275+780||115nF
120+820||110nF
350+1000||210nF
0+900||30nF
600+2.16uF
900+1uF
900+2.16uF
600+1uF
Global

I can also adjust the gain from PSTN to SPA which I have done previously.
I will try out the other impedance settings.