Plus Programming
8.7
Pie Line Support
The multipurpose line board provides system interface for loop start lines, ground start lines, and E and M tie
lines. These are typically the three different line types that the central office (CO) makes available for connection
to the public switched network. The tie line connections (also known as tie trunk access) are special circuits that
allow, on either a dial-up or a continuous connection (hot line) basis, the DXP
Plus
to communicate with remotely
located equipment such as: another DXP
Plus,
a PBX, or other common carrier (OCC) equipment for long
distance calls.
NOTE: Tie lines are primarily for incoming calls to a
Plus and depend upon
controlling
the remote site.
Tie lines can be a part of a private or leased network and can be metallic, carrier current,
or microwave. The E
and M line provides control signalling between local and remote systems. When a local DXP
Plus
puts a request
for service 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.
Tie Line Paramefers
Tie Line Types (Connect Mode)
Description:
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
(CO) interface;
however, some
also provide a metallic connection interface.
Programming:
Refer to
Section
Tie Line Standard-Protocol Signalling
(Control
Description:
The system can respond to either one of three different standard-protocols of E and M signalling. They are known
as: immediate signalling,
wink signalling,
and
delayed signalling.
You must program the desired protocol type to
match that provided by the CO or the remote equipment.
Immediate Signalling:
With this signalling method, the called DXP
Plus
answers as soon as the calling DXP
Plus
initiates the call. This signalling method is usually used if the line is programmed for hot line operation or is
programmed for pulse dialing. It is best to avoid this type of signalling in any other circumstances.
Wink
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 this 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 most useful if the DXP
Plus
is connected to another manufacturer’s PBX with
incompatible wink timing parameters.
Programming:
Refer to
Section
8-24 Line
Features Programming
