Telephone network accessing equipment

The invention relates to telephone network accessing equipment. A telephone is automatically accessed into a PSTN (published switched telephone network) and a VoIP (voice over internet protocol) network by double relays and a belling detection circuit. When the telephone network accessing equipment detects a belling signal of the PSTN call, the telephone is switched into the PSTN by the first relay and the second relay, so as to process the PSTN call. When the PSTN call is finished, the telephone is switched into the VoIP network by the second relay. The telephone network accessing equipment has the advantage that the automatic switching between the PSTN and the VoIP network is realized.