> Basically, I want a phone that instantaneously creates a perfect open
> circuit between TIP and RING upon hangup, probably with the press of a > button.
the ringer is active, there will be some leakage between tip and ring.
Phones with crappy piezo warblers will usually have much higher ringer
impedance than phones with conventional bells.
"C'est un Nagra. C'est suisse, et tres, tres precis."