Vertical comdial DX-120, Installation And Maintenance Manual

Page: 24 / 146

O
VERVIEW
DX-120 Installation and Maintenance Manual
- 18 -
408M (KSU1 Component)
The 408M is the large circuit board that is packaged inside of KSU1. The 408M provides interface for up to four
loop-start CO lines and 8 digital extension ports. Additionally the 408M 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 408M that is connected 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.
KSU1 shown with cover – CPM and APM4 removed (408M exposed)
•
The 408M is equipped with a heartbeat LED that indicates processing activity on the PCB. The 408M
peripheral processor is operating when the heartbeat LED is flashing. The KSU1 operation LED (located
next to the power switch) is tied to the 408M heartbeat LED. Therefore, when the LED next to the power
switch is flashing, the 408M is active.
•
The KSU1-408M has three ribbon cables:
-
located at the upper right and oriented in a horizontal position, the J1 cable is used to interface a COM4 if
required to expand the system CO line capacity.
-
located at the upper center and oriented in a vertical position, the J4 cable is used to interface the DX-120
CPM.
-
located at the upper center and oriented in a vertical position, the J5 cable connects to the standard
APM4 installed in KSU1.
•
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.
408M - KSU1 Component (continued on next page)
Power Failure
Port
APM4 Ribbon
Cable
CPM Ribbon
Cable
COM4 Ribbon
Cable
8 Digital
Extension Ports
4 Loop Start Co
Line Ports