AddPac Technology's Official Blog.: AddPac E&M VoIP Module Interface Type, AddPac 4 Port E&M VoIP Card Hardware Specification

Various E&M VoIP gateway series of AddPac Technology is approved for its high performance and reliability in world-wide markets. AddPac provides highly advanced VoIP services in order to meet demanding and evolving business requirements of customers. Especially AddPac E&M VoIP Gateway has been developed through more than 10 years of experiences and accumulated know-how from existing enterprises and communication markets. AddPac E&M VoIP Gateway provides concurrent dual stack such as SIP, H.323 and advanced QoS service for high quality VoIP communication service.

To meet various E&MInterface types in legacy PBX field, AddPac E&M VoIP Module supports the existed all E&M interface types like as Type I, II, III, V. by hardware jumper setting.

First, E&M Type I

Type I is the most common standard type in North America and Japan, etc.The E&M VoIP gateway grounds its E-lead to signal a trunk seizure. The PBX applies the battery to its M-lead in order to signal a seizure. E&M VoIP gateway expects to see off-hook conditions on the M-lead and signal off-hook to the remote device on E-lead

Second, E&M Type II

The Type II interface requires no common ground; instead, each of the two signals has its own return. For the E signal, the tie line equipment permits current to flow from the PBX; the current returns to the PBX's ground reference. Similarly, the PBX closes a path for current to generate the M signal to the tie line equipment.

Third, E&M Type III

A variation of Type II, Type III use the SG lead to provide common ground. With this configuration, the PBX drops the M signal by grounding it, rather than by opening a current loop.

Fourth, E&M Type V

Type V is a simplified version of Type IV. This is also a symmetric interface using only two wires. Type V requires a common ground between the PBX and the tie line equipment; this is provided via the SG leads.