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In telephony, an arrangement that uses separate leads, called the E lead and M lead, for signaling and supervisory purposes. The near end signals the far end by applying -48 VDC to the M lead, which results in a ground being applied to the far end`s E lead. The E originally stood for ear and the M originally stood for mouth.

The analog E&M trunk interface in Telesis systems satisfies conditions for AT&T Type-V connection. The interface may individually be set to either a two- or four-wire interface by appropriate configuration of the on-the-board jumpers. Xymphony supports many different line and register signaling types over the E&M lines. An additional detector on the M-wire checks the DC feed on the line for faulty conditions at far-end equipment. The reference impedance is 600 ohm resistive. The interface can be programmed as incoming, outgoing, both-way trunk, or unavailable.

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Page last modified on June 23, 2010, at 08:36 AM EST
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Iskitler Cad. No.68 Ankara, TURKEY. Tel: +90 312 3840540 Fax: +90 312 3840549