ELECTRONIC BRIDGE BETWEEN MOBILE-TELECOMMUNICATION DEVICE AND PUBLIC-SWITCHED-TELEPHONE-NETWORK (PSTN) OR VOICE-OVER-INTERNET-PROTOCOL (VOIP) DEVICE

In an embodiment, a bridge circuit is configured for connecting a desk phone (e.g., a VoIP phone) to a mobile device (e.g., a smart phone), while allowing the existing desk-phone VoIP/PSTN system (e.g., a PBX system) to be eliminated with significant savings in reduced telecommunication-infrastructure costs. The bridge circuit can be powered through traditional wall power, and can include a CAT 5 cable port with Power Over Ethernet (PoE), a PSTN port such as an RJ11 port, a set of electronics that provide wireless connectivity to the mobile device, a control circuit, and a set of software instructions for programming the desk phone to communicate with the bridge circuit and for providing other features such as conference calling, putting a call on hold, and transferring contact information from the mobile device to the desk phone or vice-versa.