· E&M/Magnet Voice Gateway developed by NICEUC is a solution with excellent quality and reasonable price for dispatching industry (especially dispatching in Amy, Railway). It is E&M VoIP gateway that on basis of IP, provides with stable network configuration, powerful functions and features, excellent voice quality.
· E&M supports three variants of E&M: Type I, Type II and Type V.
· Maximal quantity of E&M interface is 96 ports and 128 SIP trunks in one box. Meanwhile, other interfaces like FXS/FXO, GSM/CDMA/WCDMA are available for E&M voice gateway in our company.
· E&M is a common trunk signaling technology for telephone switches and PBX. E&M signaling unit and trunk circuit are separated.
· E&M (earth & magneto, or ear & mouth) is a type of supervisory line signaling that uses DC signals on separate leads, called the "E" lead and "M" lead, traditionally used in the telecommunications industry between telephone switches.
· E&M signal is defined as one connection type between trunk circuit and signaling unit.
· E&M voice gateway receive E signal from PBX, and transmit M signal to PBX. E&M interface always connects with PBX. Devices with E&M interface can only be connected with devices that have E&M interface.
Parts of E&M
E&M interface is made of four parts, they are:
1. E&M signaling and wires (Type I to V):
(1). E signal wire (Ear);
(2). M signal wire (Mouth);
(3). Signaling Ground (SG);
(4). Signaling Battery (SB);
2. Audio channel (2-wires or 4-wires)
(1). T/R (Tip/Ring): T/R wires used for transmitting and receiving between signal unit and trunk circuit. In 2-wires circuit, the working mode of this pair wires is full duplex audio channel.
(2). 1/R1 (Tip-1/Ring-1): only used in 4-wires circuit. Stand of 4-wires define specific channel that used for transmitting and receiving audio signal.
4-wire E&M uses a 4-wire (2-pair) transmission path for the voice signal. 2-wire E&M uses a single pair for both transmit and receive voice signal. This is much inferior to 4-wire E&M as the 2-wire interface uses hybrid transformers which reduce signal quality and can introduce echo.
3. Start signal mode (Immediate Start, Wink Start, Delay Start)
4. Address signaling information (Pulse, double voice multiple audio DTMF)
Multiple access way
· GSM trunk;
· E1 port, support ISDN PRI, SS7, R2, V5.2, Q.SIG, DPNSS;
· IP trunk which is based on SIP and IMS, are compatible with CISCO/AVAYA/HUAWEI/ ZTE /NOTEL/ALCATEL, etc.
Management and maintenance methods
· Local and remote WEB management;
· Local and remote Telnet command line management;
· Console port - super terminal management;
Voice processing technology
· Voice Activity Detection (VAD);
· Comfort Noise Generation (CNG);
· Echo cancellation (Echo Cancellation);
· Dual-tone multi-frequency signals (DTMF) generation / detection;
· Caller ID (Caller ID) generation detection;
· Flexible input / output gain control;
Slot for PSU
1 to 2 (Hot-standby)
Slot for MCU
1 to 2 (Hot-standby)
E&M or Magnet Port
4 to 16
4 to 8
4 to 32
4 to 96
16 or 32
32 or 64
Other Optional Port
FXO / FXS, GSM / CDMA / WCDMA /4G LTE, Radio, Audio, etc.
E1 / ISDN, FXO / FXS, GSM / CDMA /
WCDMA /4G LTE, Radio, Audio, etc.
1 (10/100/1000M Base-T)
2 (10/100/1000M Base-T)
or AC 110-240V
or AC 110-240V
DC -48V or AC 110-240V (Redundancy)
1. IP expansion for base station of analog radio
EM Gateway is mainly used for IP expansion between dispatching and base station of radio in the radio dispatching system. Through the IP network, it can deploy base station of analog radio in a wider range. (For example: 350M base station of analog radio).
2. Remote interconnection for PBX with E&M trunk interface
EM gateway is also used for IP expansion for traditional PBX with E&M trunk or dispatching system.