GDK-100
DIGITAL KEY TELEPHONE SYSTEM
16
There are two kinds of PSUs; PSU1 and PSU2. See the clause; table 2.3.3 and the clause 3.3.5.
2.4.4 RGU (Ring Generator Unit)
The Ring Generator Unit provides the Ring voltage to the SLIB circuits to ring the SLT. Also the RGU
provides the input to the Message Wait source on the SLIB cards. The output of the RGU is 90VAC, 20
Hz or 25 Hz. Two RGU versions are available; one is internal type, the other is external type. The internal
RGU can support simultaneous ringing for 5SLTs and the External RGU for 10SLTs.
There are 7 kinds of RGUs as followings,
- RGU1: 20Hz step sine wave, external
- RGU2: 25Hz step sine wave, external
- RGU3: 20Hz step sine wave, internal
- RGU4: 25Hz step sine wave, internal
- RGU5: 25Hz pure sine wave, external
- RGU6: 25Hz pure sine wave, internal
- RGU7: 20Hz pure sine wave, internal
One of them can be selected and installed according to the desired capacity of ring and the
requirements of local regulations.
The internal RGU is fitted on the lower right side panel inside the basic cabinet, the external RGU is
mounted suitable place outside the cabinet. And all RGUs are electrically connected to the back plane,
regardless of RGU type.
2.4.5 PFTU (Power Failure Transfer Unit)
The PFTU provides the relay contacts for transfer of 6 CO Lines to 6 SLTs in the event of a power or
processor failure. The PFTU is installed outside of the KSU and up to 5 PFTU modules can be connected
to the KSU with the cascade connection of control wire. The PFTU is equipped with a manual switch that
activates the Power Failure Transfer mode for testing purpose.
A 2-pin connector with screws is fitted for the control signal. And a RJ21 type male connector is fitted for
the connection between CO line, CO interface circuit, SLT interface circuit and SLT.
