Ring Voltage Adjustment

Fusion Voice service, features and help.
5 posts Page 1 of 1
by cbritton » Tue Jan 09, 2018 11:10 am
I have a vintage rotary phone I am trying to hook up to my Sonic VOIP. I have a pulse dial to tone converter to hopefully allow me to dial out, but am having issues with the ringer. Using my Voltmeter, I can see I am getting 48V at 20Hz from the wall jack when the phone rings, not the 90V at 20Hz as required for an old phone such as this. The phone therefore does not have enough voltage to strike the bells. Just wondering if there's a way to boost the ring voltage either locally, or through settings Sonic customer service might have access to.
by big_g » Tue Jan 09, 2018 3:16 pm
48 volts? WHAT? I've never seen a phone ring on 48 volts. I spent over 25 years at AT&T, and it was always 85 to 105 volts AC (20Hz).
48 volts DC was the standby voltage normally available on an idle line.
That was then, before VOIP. All signaling and power came from the Central Office on that copper wire pair. A VOIP device (i.e. the Sonic modem sitting on your desk) only gets a very small signal through the internet, then depends on local power (from your AC outlet) and conversion circuitry inside the modem, to create ring voltage and talk voltage.

You might research the requirements for ring voltage in the VOIP industry... hope that helps. An
by wa2ibm » Tue Jan 09, 2018 5:20 pm
Your old phone requires quite a bit of current to make it work. It's a bit expensive, but here's an example of a ring voltage amplifier that would work:

http://phoneman.com/ring-voltage-booster-ii.html

You might be able to find something cheaper.

Bill
by cbritton » Tue Jan 09, 2018 8:00 pm
Checked again tonight, and I am for sure getting 48V at 20Hz out of the socket. In my research of the little Sonic box, a Grandstream HT701, it has a function for high ring power, with the default setting being off. I followed the instructions in the GrandStream manual to attempt access to these settings (*** to access voice prompt, then 02 to find the IP address, and then type IP address into web browser to obtain access to settings login), with my 3 web browsers all saying they could not reach the site. Perhaps a block by Sonic to maintain control. I will continue to investigate, but its quite a bit of effort for just making a cool old phone work.

I looked into that ring booster, but really don't want to spend that kind of cash on a conversation piece of a phone. Oh well.
by dragonsclaw » Thu Jan 11, 2018 8:30 am
Many meters will read the DC component when on the AC scale. Older Simpson 260/270 had an extra 'Output' (really an Input to the meter) jack that had a .1uF in series to the + internally. This is a DC blocker which allow the reading of the AC component.

CO ring voltage was 105V, PBX was 85V

x-Pacbell frameman, x-BNR (Nortel) Sr Tech
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