HP J4900B User Manual

B-2
Switch Ports and Network Cables
Switch Ports and Network
Cables
Because of the increased speed provided by 1000Base-T (Gigabit-T), network
cable quality is more important than for either 10Base-T or 100Base-TX.
Cabling plants being used to carry 1000Base-T networking must comply with
the IEEE 802.3ab standards. In particular, the cabling must pass tests for
Attenuation, Near-End Crosstalk (NEXT), and Far-End Crosstalk (FEXT).
Additionally, unlike the cables for 100Base-TX, the 1000Base-T cables must
pass tests for Equal-Level Far-End Crosstalk (ELFEXT) and Return Loss.
When testing your cabling, be sure to include the patch cables that connect
the switch and other end devices to the patch panels on your site. The patch
cables are frequently overlooked when testing cable and they must also
comply with the cabling standards.
Fiber-Optic Cables
Port Type Cable Specifications Connector Type Maximum Length
Gigabit-SX 62.5/125 mm or 50/125 μm (core/cladding)
diameter, graded-index, 850 nm, low metal
content, multimode fiber-optic cables,
complying with the ITU-T G.651 and ISO/IEC
793-2 Type A1b or A1a respectively.
LC - Gigabit-SX
mini-GBIC
• 62.5 μm cable:
– 160 MHz*Km=220 meters
– 200 MHz*Km=275 meters
• 50 μm cable:
– 400 MHz*Km=500 meters
– 500 MHz*Km=550 meters
Gigabit-LX 9/125 μm (core/cladding) diameter, graded-
index, 1310 nm, low metal content, single
mode fiber-optic cables, complying with the
ITU-T G.652 and ISO/IEC 793-2 Type B1
standards.
OR
the multimode fiber-optic cables listed for
Gigabit-SX.
LC - Gigabit-LX
mini-GBIC
• Single-mode cable:
10 kilometers
• Multimode cable:
550 meters
Note: To use multimode cables for Gigabit-LX, a mode conditioning patch cord may be needed - See
“Mode Conditioning Patch Cord for Gigabit-LX” on page B-3 for more information.
Gigabit-LH 9/125 mm (core/cladding) diameter, graded-
index, 1550 nm, low metal content, single
mode fiber-optic cables, complying with the
ITU-T G.652 and ISO/IEC 793-2 Type B1
standards.
LC - Gigabit-LH
mini-GBIC
70 kilometers
Note: Between the transmit and receive ends of the cable, at least 5db of attenuation is required for a
reliable connection. This is equivalent to 20 Km of the fiber-optic cable. For distances less than 20 Km,
you must add attenuators to bring the total attenuation to at least 5db. Most cable vendors carry
attenuators.

HP J4900B Specifications

General

Brand	HP
Model	J4900B
Category	Switch
Language	English