Specifications

DX-80 INSTALLATION AND MAINTENANCE MANUAL
P7290 IMM 1-7
Figure 2: KSU1 shown with cover, CPM and APM4 removed. (408M exposed)
The fourth CO Line port is equipped with CNG Fax Tone Detection circuitry. When programmed as a “FAX”
line, this circuit will automatically engage the FAX Tone detector. If FAX tone is detected, the call is routed to
the analog port designated as the destination for fax calls.
Each digital port (connects to Digital Executive Telephones and DSS Consoles) is comprised of a
proprietary octal ASIC (Application Specific Integrated Circuit) transceiver. There are three data channels in
operation at each digital port via the octal transceiver. One channel is used for call processing control of
digital terminal functions/operations and two channels are used for the digital voice channel requirements.
Each digital station interface is protected against circuit wiring shorts by an over-current protection
Polyswitch. The digital station circuit requires only one cable pair to operate and is not polarity sensitive.
Physical connection of digital extensions, power failure telephones and CO lines to the 408M module is
made through convenient RJ-11 connectors along the bottom edge of the module.
408E
The 408E is very similar to the 408M, however it is unique to KSU2. The 408E (KSU2 component) provides
interface for up to 4 loop-start CO Lines and 8 Digital Extension Ports. Additionally the 408E regulates the
24 volt DC power from the source to produce all required logic voltages and operations voltages. There is
also a Power Failure Port located on the 408E that is associated to the first CO Line circuit. Whenever
power fails this port becomes active with dial tone from the CO line connected to the first CO line port.
The 408E is equipped with a Heartbeat LED that indicates processing activity on the PCB. (The 408E
peripheral processor is operating when the Heartbeat LED is flashing.) The KSU2 operation LED (located
next to the power switch) is tied to the 408E Heartbeat LED. Therefore, when the LED next to the power
switch is flashing, the 408E is active.
The KSU2-408E connections are almost identical to those on the 408M (KSU1). The exception is the long
shielded cable used to connect KSU2 to the CPM inside of KSU1. (Also notice: that there is no standard
APM4 installed inside of KSU2.)
Each CO line circuit incorporates over-voltage protection, ring detector, loop detector, loop/pulse-dial relay,
current sink circuit, coupling/isolation transformer (impedance 600:600), hybrid circuit, CODEC & filter,
polarity guard circuit and Radio Frequency noise filter.
The fourth CO Line port is equipped with CNG Fax Tone Detection circuitry. When programmed as a “FAX”
line, this circuit will automatically engage the FAX Tone detector. If FAX tone is detected, the call is routed to
the analog port designated as the destination for fax calls.
Power Failure
port
Four Loop Start
CO Line ports
COM4
ribbon cable
CPM ribbon
cable
APM4 ribbon
cable
Eight digital
p
orts