A method is provided for forwarding packets. The lower casing 12 includes a wall portion 13d arranged to stand from the inner bottom 12d, and a supporting face 13a formed integrally with the wall portion 13d from the wall portion 13d in a direction substantially parallel to the inner bottom 12d. To accomplish these pass through functions, the speech recognition system sets up what is know as a hairpin connection between the subscriber, the speech recognition system and the voice mail system. To counter this effect, the dopant concentration of the n+ region near the edge is reduced to reduce the NPN transistor beta and current along the edge, thus increasing the breakover voltage.