ipLDK-60 SERVICE MANUAL
DIGITAL KEY TELEPHONE SYSTEM
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terminal. Digital information is sent to between MBU
and Keyset, which employs a Ping-Pong technique which is used
to send voice and signaling information for that instrument. One “B” channel carries digital voice information while the
“D” channel carries signaling information for that instrument to and from digital terminal interface boards.
The GSL12 block of ACT2 on the MBU assembles and disassembles the 2B+D information packets and controls the
digital signal for transmission. Digitized voice is converted to analog voice in the instrument by the Codec device,
coder/decoder and analog voice is converted to digitized voice by the same Codec for transmission back to digital
terminal interface boards.
Signaling information sent on the “D” channel from the digital instrument to digital terminal interface boards is processed
by the micro-processor on MBU. The micro-processor processes requests and sends system status and commands by
digital terminal signaling logic in the GSL12 block to the phone.
Digitized voice information sent on the “B” channel is routed to ACT2 on the MBU for switching and gain control. The
MBU switches the information to a receive “B” channel and informs the receiving terminal on the system such as
another station.
B. Analog Instruments
Analog instruments can be used in ipLDK-60 system. Analog voice communication is sent over the single pair of wires
from the single line interface boards to the station.
CODEC on the SLT interface circuits is used to convert digital voice signals to analog voice signals before being sent to
the analog instrument and to converts analog voice from the phone to digital PCM signals before routing them through
the system.
2.1.3 Capacity Limitations
A. CO Ports
It allows max. 12 central office lines to be connected to the system.
B. Station Ports
The maximum number of station (Digital KTUs or SLTs) installed on the system is 48 (Max 32DKTs, 47SLTs).
