טלפון שבת של צומת

Shalom. I am a physician in the US and had purchased many years ago a shabbat phone form zomet. Recently I spoke to Rabi Tendler who said that the zomet phone is really a time delay switch and not the gerama that the institute for science and halacha developed. I basically wanted a means to talk to patients in situations that where permitted as long as only

derabbanins were involved. e.g. kol gufo for a jew orperhaps issues involving a non jew. I know that there are opinion that differ regarding non jews but in any case. Is there another phone that is better or is there no commercial phone that is able to lower the issues to a de'rabbonin.

Thank you for your help in this matter.