Trunk Types Description - Nortel Meridian 1 Manual

Trunk types description

4-wire E&M trunk operation (DC-5)
Intelligent peripheral equipment circuit cards for New Zealand
• Each unit on the NT5K19BA E&M Tie trunk card supports:
• 4-wire E&M Type 1 tie trunk (DC5)
• Recorded Announcement (RAN) trunk
• Paging (PAG) trunk
• Music (MUS) trunk.
The NT5K19BA E&M Tie trunk card supports the United Kingdom DC5-A
method of signalling, which is used between a Private Branch Exchange
(PBX) and co-sited equipment. The two signalling wires used, E and M, are
electrically separated from the associated speech circuit. Signals are sent on
the M wire and received on the E wire.
Send signals
All signals are sent in the form of either Earth-On or Earth-Off applied to the
M wire, where:
• Earth-On is the application of ground to the M wire through a
resistance of 1250 ohms, and
• Earth-Off is the removal of the Earth-On condition such that the
resistance to earth is greater than 500 kΩ.
In both Earth-On and Earth-Off conditions, a grounded 1µF capacitor is
applied to the M wire.
Receive signals
All received signals are in the form of Earth-On or Earth-Off applied to the E
wire, where:
• Earth-On is the application of ground to the E wire through a
resistance of 1500 ohms.
• Earth-Off is the application of ground to the E wire through a
resistance of greater than 400K ohms.
E&M tie trunk circuit card
Option 11 - Description and Instal-
Page 21 of 44