Comdial DXP Plus Series, Руководство пользователя

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1.2 Detailing E&M Signalling Methods
The multipurpose line board provides two wires for a tip and ring voice circuit and two wires (the E and M line)
to provide control signalling between the systems. When a local DXP Plus puts a request for service from the
remote equipment on the M lead, the remote equipment detects this request on its E lead. As an option it can also
respond by putting an alerting signal on its M lead.
NOTE: Intercom feature codes of one DXP Plus are not available to callers from the other DXP Plus nor can
those callers access a line through the distant DXP Plus using line group access codes.
The DXP Plus supports two different types of E and M lines. The E and M Direct type is for direct connection
between two telephone systems and is also known as a metallic connection. The E and M Carrier type is for tie
lines that run through a central office (CO) interface; however, some COs also provide a metallic connection
interface.
If you plan to use tone dial configured E and M lines with the multipurpose line board, you may need to install
one or more DTMF receiver cards to the DXP Plus. Typically, you will need one DTMF receiver for every six
lines. In high traffic situations, you may need additional DTMF receivers. For information on DTMF receiver
card installation, see IMI89–186, Installing A DTMF Receiver In The DXP Plus Digital Communications System.
NOTE: The DTMF receiver cards that you add for this purpose are in addition to any you may add to the system
to support industry-standard telephone station boards
You can program the system to respond to three different standard-protocol types of E and M signalling. They are
known as: immediate signalling, wink signalling, and delayed signalling and are defined in the following
paragraphs.
Immediate Signalling: With this signalling method, the called DXP Plus answers as soon as the calling DXP
Plus initiates the call. There is no delay between calling and answering. This signalling method is usually used if
the line is programmed for hot line operation or is programmed for pulse dialing.
Wink Signalling: With this signalling method, the called DXP Plus places a momentary signal reversal (wink) on
its M lead to alert the calling DXP Plus system that it is ready to receive information. The calling DXP Plus
controls the status of the M lead and watches for a return signal from the called DXP Plus on the E lead. A wink
occurs when the called DXP Plus is ready to receive dialed digits from the calling DXP Plus. Dialing can begin
only after the wink is complete. After the wink occurs, the called DXP Plus (if it is programmed for dialing)
returns dial tone to the calling DXP Plus as an indication it is ready to receive digits. This signalling method is
the preferred protocol for use between two DXP Plus systems.
Delayed Signalling: With delay dial signalling, the called DXP Plus immediately responds to the calling DXP
Plus by sending an off-hook signal on its M lead. It holds this off-hook condition until it is ready to receive digits
and then returns its M lead to on-hook. After the signal exchange occurs, the called DXP Plus (if it is
programmed for dialing) returns dial tone to the calling DXP Plus as an indication it is ready to receive digits.
This signalling method is an alternate to wink start signalling that also provides equipment readiness signals. This
method is most useful if the DXP Plus is connected to another manufacturer’s PBX with incompatible wink
timing parameters.
In addition to the standard-protocol signalling, you can program the system to respond to two types of
non-standard tie line signalling protocols. They are known as: hot line and intercom dialing and are defined in the
following paragraphs.
Hot Line: You can program the system for hot-line operation so that as soon as a user accesses the tie line, the
station or stations at the distant system that have access to the personal or group intercom assigned to the hot line
will ring.
Intercom Dialing: Alternately, you can program the system for intercom dialing mode so that as soon as users
access the tie line they will hear dial tone. Upon hearing dial tone, they can dial either a personal or group
intercom number at the distant system.
IMI89–192 Installing The Multipurpose Line Board
2 – Installing The Multipurpose Line Board