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• Always use an isolating transformer with weather FAX audio cables.
• Always use an RS-232/NMEA converter with optical isolation on the signal lines.
• Always use PC's and other devices that are directly DC powered.
Cables and cable runs
When installing system cables consider the following:
• All cables should be adequately secured, protected from physical damage and
exposure to heat. Avoid running cables through bilges or doorways, or close to
moving or hot objects.
• Acute bends must be avoided.
• Where a cable passes through an exposed bulkhead or deckhead, a watertight
feed-through should be used.
• Secure cables in place using tie-wraps or lacing twine. Coil any extra cable and tie
it out of the way.
• Do not pull cables through a bulkhead or deckhead using a cord
attached to the connector. This could damage the connections.
Proper cable shielding
For all but the shortest length cable runs, data cables must be shielded to prevent them
from picking up electrical noise from other devices, and to keep them from radiating
potential interference. If you encounter a data corruption problem, a good place to
begin troubleshooting is with the cable shielding, especially on longer cable runs.
Make sure the cable shielding hasn't been scraped off by being squeezed through a
tight area.
Preventing interference and crosstalk
You should always run data cables:
• as isolated as possible.
• as far away from high current carrying AC and DC power lines as possible.
• as far away from antennas as possible.
While it may be convenient to bundle power and data cables together, this causes
crosstalk between them, which results in scrambled and unusable data. If you must
cross a power cable when running a data cable, try to make the crossing as close to 90
as possible; never run power and data cables parallel within the same bundle.
If you have long cable runs planned for data cables, and are using NMEA equipment,
use a shielded twisted pair cable to eliminate the danger of interference and crosstalk.
RayTech RNS - Getting Started
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