GE Mark VIe System Manual page 97

3.7.3 Ethernet Installation
The data highways use a number of 100Base-TX segments and some fiber-optic segments. These guidelines comply with
IEEE 802.3 standards for Ethernet. For details on individual Ethernet LAN component installation, refer to the instructions
supplied by the manufacturer of that equipment. For more information, refer to the section
Note If the connection within a building and the sites share a common ground, it is acceptable to use 100Base-TX
connections. If connecting between buildings, or there are differences in ground potential within a building, or distances
exceed 100 m (328 ft), then 100Base-FX fiber is required.
3.7.4 Network Retrofit Guidelines
Existing sites should upgrade from Allied Telesis to Cisco switches, and use single-mode fiber (SMF) for all ICS VLAN
trunks. These required Cisco network switches can use SFPs with LC connectors to connect to multi-mode fiber (MMF),
however this is not recommended because it downgrades them to only 100 Mb speed (with SMF, the switches function at Gb
speeds).
Note GE recommends replacing MMF with SMF. If not, the network is downgraded to only run at 100 MB speed.
The GE requisition engineer needs to understand the ramifications if existing sites have MMF runs and the options for
retermination of Ethernet cables, changes to junction boxes, and so forth. Only a certified cable installer (not the GE field
engineer) can do any changes to MMF sites. Also, it is not recommended to use a converter from MMF SC connector to
single SMF LC connector as this can cause network latency or introduce an additional failure point.
Note Refer to the figure in the section
The options for supporting the new network switch architecture are as follows:
• Re-terminate existing MMF with LC connectors to connect to the SFPs. This downgrades to 100 Mb speed, and requires
a certified cable technician.
• Use SC to LC conversion part (323A4747CSP1G). This is not recommended as it can introduce network latency and
another possible point of failure. In addition, it still downgrades network to 100 Mb speed.
• Run new SMF cables and use new Cisco switches to full capabilities of Gbit speeds (preferred solution).
3.7.4.1 MMF Cable, Outdoor Use (Data Highways)
Warning
The following MMF cables are approved for use:
• Multi-mode fiber, 62.5/125 µ core/cladding, 850 nm infrared light
• Four sub-cables with elastomeric jackets and aramid strength members, and plastic outer jacket
• Cable construction: flame retardant pressure extruded polyurethane. Cable diameter: 8.0 mm (0.31 in). Cable weight: 65
Kg/km
• Optical Cable Corporation part number: RK920929-A
The following sections provide more details on existing site MMF cabling specifications.
Ethernet Networks
SMF and Trunks that displays the LC connector and SFP.
Never look directly into a fiber because some longer links use lasers, which can cause
permanent eye damage. Most fiber links use LEDs, which cannot damage the eyes.
Public Information
Cable Separation and
GEH-6721_Vol_I_BP System Guide 97
Routing.