🚀 go-pugleaf

The diode trick won't work in most (almost all) areas anymore.
Portable tone dialers are everywhere now, so turning off the pad is
useless, and some people actually know about hookswitch dialing (wow).

Call NTD at (800) 426-1024 and buy one of these:
HY-ULT1A- programmable, can block specific prefixes and area codes (900
and 976 for example), line powered, tone and pulse, very small.
Allows toll calls to authorized users with access code (changable).
Should be wired in series with all phones you wish to restrict.

Wholesale (pretend to be a dealer) price $59.98

NTD also stocks many nice, cheap phone systems and accessories. My
personal favorites being the Panasonic KX-T 61610, KX-T 30810 and KX-T
123211 hybrid key systems/PBXs. You can plug all your single line stuff
into them and dial 9 to get out, transfer calls and other PBX type
stuff including toll restriction, music on hold, speed calling,
forwarding, conferencing and a printed record of all calls, durations,
etc. Cheap!

Did I wander?

-- 

joe@mojave 
"I really hate my dumb job."
"People are always telling me what a great (gag!) voice I have."