Specifications

10BASE5 Ethernet Network Design
7-2 Ethernet Network Design
The coaxial cable can be run in one continuous length or in sections, joined
using N-type connectors and N-type barrel connectors. If the cable is
installed in segments and connected together, IEEE recommends that the
segments should be an odd multiple of 23.4 m in length. These special
lengths of cable are used to minimize signal reflections caused by the
insertion of connectors and barrel splices. The segment lengths are
optimum lengths and it is sometimes difficult to adhere to these
specifications in the real world. If it is not possible to adhere to the above
cable lengths, attempt to connect the cable segments at annular rings.
To further reduce signal reflections, the cable segments should come from
one manufacturer to minimize cable discontinuity problems such as
differences in propagation speed or impedance.
Transceiver Placement
The terminated coaxial cable is now ready for the placement of the
transceivers. Transceiver taps can be made into the coaxial backbone by
one of two ways:
1. Intrusive: By cutting the coaxial cable and installing connectors that
screw into the transceiver. This method of tapping is known as an
intrusive tap because the coaxial cable must be severed for the
transceiver to be connected.
2. Non-intrusive: By drilling a hole into the coaxial cable with a special
tool and clamping the transceiver assembly in place. This method is
known as a non-intrusive tap because the coring process, when done
properly, allows the tap to be made without interruption of network
traffic on the coaxial segment (see Figure 7-2).
Figure 7-2. A Non-intrusive Coaxial Cable Tap
Transceiver
Contact
Tap Pin
Compression
Screw
Coaxial Cable
Annular Ring
1913-19