Is there a way to directly access Digital Voice's SIP

[Elflord]

I'm looking to buy a new cordless phone system, but everything out there for home landline POTS is cheaply made, overpriced, primitive junk.  I wanted to put together my own VoIP solution, based on corporate handsets.

So as to not introduce even more line delay, or lose my phone #, I'd like to be able to connect directly to DV's SIP trunk, rather than get my own FXO to SIP adapter.

Right now, my call flow is looking like this:

Verizon > ONT-SIP end-point > ONT-FXS > POTS PSTN (analog phone line) > FXO/SIP server > VoIP phone

I'd like to simplify that to:

Verizon > SIP > VoIP phone

A plus is if the SIP can be provisioned over the ONT's ethernet port, without also switching internet over, as I'd like to use a seperate router for my end of the VoIP flow.

[tns2]

I am pretty sure there is no way to access Digital voice other than POTS.