Installation guide

Page 2-6
SPECIFICATIONS/REQUIREMENTS
• Noise - Noise is caused by either crosstalk (signal coupling
between the different cable pairs in a multi-pair cable, or
externally induced impulses. External noise can cause data
errors if impulses occur at very specific times during data
transmission. Generally you do not have to be concerned
about noise. If you suspect noise related problems, reroute
the cable or eliminate the source of the impulse noise.
• Temperature - Most multi-pair PVC 24 AWG telephone
cables typically have an attenuation of approximately 8 to
100 dB/100 m at 20°C (68°F). The attenuation of PVC
insulated cable varies significantly with temperature. At
temperatures greater than 40°C (104°F), we strongly
recommend that you use plenum rated cables to ensure that
cable attenuation remains within specification.
2.3 10BASE-2 NETWORK DESIGN GUIDELINES: MR9T-C
This section describes guidelines for transceivers and network
devices that connect to Port 9 of the MR9T-C. These devices must
meet IEEE 802.3 10BASE-2 standards. Ports 1 through 8 must meet
10BASE-T guidelines, as described in the previous section.
• Segment Length - The IEEE 802.3 10BASE-2 standard
requires that thin-net link length be no greater than 185
meters (607 feet). A thin coax cable can have a maximum of
30 taps. Taps must be at least 0.5 meters apart.
• Termination - Terminate both ends of a cable segment with
a 50 ohm terminator. The MR9T-C has an internal, switch-
selectable, 50 ohm terminator. When enabled, the internal
terminator eliminates the need for connecting the repeater to
the cable with a tee connector and external 50 ohm
terminator.
• Grounding - The BNC port is NOT connected to earth
ground.
Warning: For safety, all thin coax cable segments must have a single
earth ground. Cable segments that are grounded at more than one
point on the segment can develop dangerous ground currents.