ND-71548 (E) CHAPTER 2
Page 11
Issue 2
INSTALLATION DESIGN
5.2 Wall
Switching Equipment Room
• A concrete wall is necessary so that cable racks can be installed (unless a free-access floor is used).
• It is recommended that the walls be painted so that the wall materials do not generate dust, etc.
• The maximum difference in level at the wall surface should be less than +5 mm (0.2 inch).
5.3 Ceiling
Switching Equipment Room
• The required ceiling height is more than 2.3 meters (7.5 feet).
5.4 Lighting Facilities
1. Switching Equipment Room
• Fluorescent lamps are recommended.
• No less than 200 lux at the floor level is necessary.
2. Operator Room
• Fluorescent lamps are recommended.
• No less than 200 lux at the floor level is necessary.
3. Battery Room
• Anti-explosion type lamps must be utilized.
• No less than 150 lux at the floor level is necessary.
6. POWER SUPPLY REQUIREMENTS
6.1 Main Source Power
The PBX requires an operating power of -48 V DC ±5V DC. This DC operating power is supplied from the rec-
tifier which receives AC power from the commercial AC power source. For greater system reliability, it is rec-
ommended that the PBX be supplied with backup DC operating power for a predetermined duration from the
batteries installed as the auxiliary power supply source.
The batteries for the PBX must be connected in parallel with the -48 V DC output of the rectifier. Also, when
installing batteries, an EMF panel must be placed in-line (series) with the input -48 V DC supplied to the PBX.
This panel is necessary when changing the state of the rectifier from float to equalize and vice versa.