Of course, rigid drain pipes or conduit aren't always flexible like
electrical cables.

Nor entirely practical. My old phone line goes through a PVC pipe.
Problem is, water gets into the pipe and when Winter time comes 'round
and there goes my landline. I hadda run a above ground line, instead.
Sometimes, still gets wet and drops out, but at least I can access it and
fix it when it does.

You probably just need cable rated for underground use. I asked our phone
company what wire to use and they gave me a couple hundred feet for free.
Really surprised me.

If your original wires were in PVC conduit, it should be a simple matter to
pull in new cable as you pull out the old.

Of course, I now get my phone service through our cable internet, and the
individual phones are wireless. We don't even use the old phone wiring
anymore.

Anthony Watson
www.mountainsoftware.com
www.watsondiy.com