Bosch Building Technologies

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    How to prevent data noise, crosstalk, EMI, RFI and AC Inductance in data wiring.

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     Data Noise includes RFI, EMI, and AC Inductance.

    Do not install the control panel in electrical or phone rooms without first ensuring a noise-free route for the wiring and a verified earth ground. Avoid noise-generating devices. Typical noise generating devices include the following:

    • Theft scanners.
    • Bar code scanners.
    • Large transformers.
    • Telephone equipment.
    • RF equipment.
    • Florescent lights.
    • Paging systems.
    • High-voltage relays.
    • Coiled phone cords.
    • Other coiled wire in the control panel enclosure.

    Move wires 2 ft. (0.6 m) away from noisy conduit and devices to prevent noise from being induced into the data line. When your data must inevitably cross the path of AC, intersect it in a perpendicular manner, not diagonally, to minimize the extent of interference. Use a minimum 22 AWG (0.8 mm) stranded wire (18 AWG (1.2 mm) recommended for longer wire runs), preferably quad with two twisted pairs, so the extra wires can be connected to the control panel’s Common terminal to supplement the noise reduction. ZONEX 1 and 2 are different data outputs, as are the data outputs for keypads. Do not run them in the same jacket of wire. Separate, insulated twisted pairs that are adjacent to each other are acceptable. Use shielded wire for each data pair if two separate data pair share a single conduit. ZONEX 1 and 2 are separate data pairs. Do not allow phone cord to run across POPEX modules or coil next to loop wires inside the enclosure or on field runs.

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