Installation manual

D9124 Operation & Installation Manual
Page 24
© 1996 Radionics
74-06799-000-D 2/96
EMI (Electromagnetic Interference) may cause problems: EMI may occur if you install
a ZONEX system, or run wires near the following:
• Radio station transmitter site or other broadcast station
• Ham radio transmitter site
• Computer network system
• Heavy machinery and motors
• PBX telephone system
• Welding shop
• High voltage electrical equipment or transformers
• Public service (police, fire department, etc.) using radio communications
• Electrical lines, fluorescent fixtures, or telephone cabling
If you think EMI may be a problem, use shielded cable. The drain wire for the shielded
cable must have continuity from terminal 4terminal 4 on the D9112 board to the end of the wire
run. If continuity is not maintained, the shielded cable may aggravate potential noise
problems rather than eliminate them.
Only connect the drain wire to terminal 10 terminal 10 on the D9112LTB: Connecting the drain
wire to a terminal other than terminal 10terminal 10 may also produce problems. If you cut the
drain wire to install POPITs, be sure to splice it together. Solder and tape all splices.
Figure 13: Checking Resistance of Data Loops
Ω
POPIT
60 Ω MAXIMUM
SHORT ENDS TOGETHER
FOR TESTING ONLY
OHMMETER
Regardless of wire gauge or distance used, total resistance of the D8125 POPEX Data
Loops cannot exceed 60 Ω. To determine total resistance, tie the ends of the D8125
POPEX Data Loops together to eliminate POPIT resistance (see Figure 12 ). After
measuring resistance, untie the ends of the D8125 POPEX Data Loops.
Table 6: Resistance by Wire Gauge
Wire Gauge Ohms per 1000 ft.
12 1.62
14 2.58
16 4.09
18 6.51
20 10.40
22 16.50