There are a number of VRS providers out there.
What you want to do is "single-line VCO". With this, your voice channel is setup at the same time as your video call and runs as a parallel RTP stream.
What i711.com (Purple) is asking you to do is "dual-line VCO", where another call is made to bridge your voice through the Public Switched Telephone Network (PSTN).
All of the VRS providers support dual-line VCO.
Only a couple of VRS providers support single-line VCO, most do not. Here is a quick list of the VRS platforms out there today:
- ZVRS [zvrs.tv or (888)888-1116] (aka CSDVRS) - supports single-line VCO (marketed as VCOPlus)
- SNAP [snapvrs.tv] - supports single-line VCO
- URrelay [urrelay.tv] - ?
- LifeLinks [llvrs.tv] - ?
- AmericanVRS [americanvrs.tv] - ?
- Purple [i711.tv] (aka HOVRS) - no single-line VCO
- Sorenson [svrs.tv] - no single-line VCO
Believe it or not, all of the other VRS providers out there are on one of those VRS platforms. Ping the DNS name, and note the IP address. Note how there are only a handful of unique IP network addresses involved for all VRS providers. There are only a handful of actual VRS platforms available, that is why.
You can dial-around from your video client by dialing another provider's phonenumber or DNS name.
Many VRS videophones, like the VP200, either have horrible microphones or don't do audio at all, so single-line VCO calls are not possible from those.
I've heard that the Purple P3 doesn't support audio at all, so single-line VCO calls are probably not possible with it either (I'm on a Mac, so I've never tried myself).
The ZVRS Z4 and SprintVRS SV4 clients (Mirial based, run on both PC and Mac) support single-line VCO, as do their respective VRS services.
If you happen to be lucky enough to still have a Viable Vision account, that's an older Mirial client that should (might?) support single-line VCO as well.
There are other video clients out there. I recommend looking around and contacting that VRS provider's tech support to help you get going. That's what they are there for.
Cheers!