On 2005-10-18, wrote:
the relay (soldered) has approx 20kohms between the coil and 200k
between the output, when dis/reconnecting the dialtone returns but then
again goes busy by itself!

That first figure sounds way too high, 200 ohms would be the low side of
believable can you check again?

seing as it doesn't look like a short

also can you measure the current through the modem when it's connected to the
phone line (but on hook/powered off) a ohm meter running at 1.5-9V soetimes
sees things differently to the phone line (48V on-hook)

Is it possible you've measured the ring detector and not the relay?

Bye.
Jasen