GDK-100
DIGITAL KEY TELEPHONE SYSTEM
23
2.4.10 Analog CO Line Boards
GDK-100 Analog CO line Boards have capable of supporting various types of analog CO line as
followings,
Board
Function
connection
LCOB
Provides Loop Start CO interfaces, 4 interfaces
2 wire
AC15
Provides AC15a signaling interfaces, 3 interfaces; UK
4 wire
EMIB
Provides 2-wire E&M interfaces, 4 interfaces; Korea
4 wire
DIDB
Provides Direct Inward Dialing interfaces, 4 interfaces; Korea
2 wire
BWDIDB
Provides Both-way DID interfaces, 4 interfaces; New Zealand
2 wire
!
Note
Analog CO line Boards except LCOB are designed to comply with special national specification and
application, so it may not suitable for the other national specification and/or application.
2.4.10.1 LCOB (Loop Start CO Line Interface Board)
LCOB provides 4 CO/PBX Loop Start CO Lines which support pulse /DTMF signal. Each Interface
contains ring and loop current detection circuits, A/D and D/A conversions, and pulse and ground flash
signaling circuit. LCOB contains 4 LEDs to indicate the status of each CO line.
RJ21 type male connector is mounted on the front edge of the LCOB for the connection to lines.
LCOB can be optionally equipped with up to 4 Call Metering Units (CMU) to monitor call charge, a Call
Progress Tone Unit (CPTU) to monitor call progress tone and a DTMF Receiver Unit (DTRU) to detect
DTMF.
A CMU supports call metering function and can be installed on each line. And the appropriate type of
CMU should be installed on the line according to the national specification.
Each CPTU contains two tone detection circuits that are time shared under software control as system
resources. These detectors are used in support of several features such as ACNR. If such features are to
be used, it is recommended that at least one CPTU be provided for every LCOB. According to sensitivity
of tone detector, two types of CPTU (CPTU/A, CPTU/B) are available. CPTU/A has wide tone detection
range(305Hz~640Hz) and CPTU/B has narrow tone detection range (350Hz, 620Hz, 440Hz, 480Hz
±
1%).
LCOB can be installed in any of slot No. 1-12.
Analog CO interface boards are limited by maximum 32 analog lines in a system.
Add-on boards: DTRU, CPTU/A, CPTU/B, CMUPR/CMU50/CMU12/CMU16/CMU12PR/CMU50PR
2.4.10.2 AC15 Board (AC15 Private Line Interface Board) - UK
AC15 board provides an analog interface between outside tone controlled private lines and the system.
An AC15 board has 3 interface circuits that support AC15a signaling and DTMF or Pulse dialing. Each
AC15 private line interface circuit provides two-pair (transmitting and receiving) audio interface circuit and
signaling to and from the system and private line.
The AC15 board contains three LEDs to indicate the status of each line.
