jcw (09/02/82)
References: mh3bs.185 Your old (or new, for that matter) dial phones will work fine with red and green (tip and ring in telco parlance) swapped. However, the oscillator in the tone pad requires power to operate, and the power must be of the correct polarity. The power is obtained from the phone line, which has a nominal 48 volts DC across it with nothing connected, and about 24 volts when 'off hook'. Nothing else in a standard phone requires a particular polarity, so you can still receive calls on your touch-tone phone wit the wires reversed.
gill (10/08/82)
#R:mh3bs:-18500:physics:15700002:000:422 physics!gill Aug 31 20:31:00 1982 As explained in a recent fa.telcom, some touch tone phones have bridge rectifiers on their line inputs. The other possibility is that your phone did indeed get zapped, but was wired differently than the replacement. This is very unlikely. The classic touch tone syptoms of reversed polarity is a slight click and perhaps a little "squeek" tone instead of the usual prolonged blast. Gill Pratt ...alice!gill OR gill@mc