FAQs

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Q: Do I need a special cable for a 100vg network?
No. 100vg will work with Category 3 and Category 5 Unshielded Twisted Pair cable. All 8 wires (4 pair) must be used and wired with the standard twisted pair assignments. In some Category 3 cable installations, only 4 wires (2 pair) are available for LAN traffic, in which case that cable cannot be used with 100vg. If you presently have a 4-pair UTP cable network that complies with the Ethernet/IEEE 802.3 Type 10Base-T specifications, you can use the same cables for your 100vg network as long as all 4 pairs are available and wired correctly.

The specifications for 100vg cable are:

• 4-pair UTP: EIA/TIA 568 standard or ISO/IEC DIS 11801 for 4-pair 100 ohm unshielded twisted-pair cable
• 2-pair STP: EIA/TIA 568 standard or ISO/IEC DIS 11801 for 2-pair 150 ohm shielded twisted-pair cable
• fiber-optic: EIA/TIA 568 standard or ISO/IEC DIS 11801 for 2-fiber 62.5/125, multimode, graded-index, optical fiber cable

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Q: How far apart can 100vg Hubs be installed?
The distance depends on the type of cable used:

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Q: What are uplink ports and downlink ports on 100vg Hubs?
Uplink ports are used to connect to upper level hubs when you are cascading 100vg Hubs. Downlink ports are used to connect to PCs and servers. Downlink ports are also used to connect to lower level hubs when you are cascading hubs.

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Q: What ports are on the HP Advancestack 100vg Hub-14 (product J2415A)?
There are 12 fixed 100vg RJ-45 twisted pair ports and two open transceiver slots. The 12 fixed 100vg ports are downlink ports for connecting PCs and servers. The two transceiver slots can hold either an HP Advancestack 100vg Fiber Optic Transceiver (product J3027A) or an HP Advancestack 100vg UTP Transceiver (product J3028A). Transceiver slot "A" can only be used as an uplink port for hub cascading. Transceiver slot "B" can be used as either an uplink port for cascading or a downlink port for PC or server connectivity. If transceiver slot "B" is used as a downlink port, then RJ-45 twisted pair port 12 is disabled.

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Q: How do I connect two 100vg Hubs together with twisted pair cable?
To connect 100vg hubs with twisted pair cable, you must use the uplink and downlink ports on the 100vg hubs. The hub that is connected to the server is called the "root level" hub. Hubs connected to the root level hub are called the "second tier" hubs, and hubs connected to the second tier hubs are called the "third tier" hubs, etc.

To connect a root level hub to a second tier hub, you connect a cable from a downlink port on the root level hub to an uplink port on the second tier hub. To connect a second tier hub to a third tier hub, you connect a cable from a downlink port on the second tier hub to an uplink port on the third hub.

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Q: Can I use a twisted pair crossover cable to connect two 100vg hubs together?
No. Since 100vg technology uses all 8 wires "straight-through" for high speed transmission, crossover cables cannot be used. Uplink and downlink ports exist on 100vg hubs to allow the hubs to be connected using "straight-through" cables.

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Q: How do I connect two 100vg Hubs together with fiber cable?
To connect two HP Advancestack 100vg Hub-14 (product J2415A) devices together with fiber cable, install HP Advancestack 100vg Fiber Optic Transceivers (product J3027A) in transceiver slot B of the root level hub and in transceiver slot A of the second tier hub. Configure transceiver slot B in the root level hub as "12B" (Downlink). Connect the fiber cable from the transceiver in slot B in the root level hub to the transceiver in slot A in the second tier hub.

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Q: How many levels of 100vg Hubs can I connect together?
You can connect up to 5 levels of hubs together. For more efficient networks, Hewlett-Packard recommends restricting the levels to 3.

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Q: How do I connect my 100vg network to a 10Mbps network?
If you have one of the following hubs:

• HP Advancestack 100vg Hub-15 (product J2410A)
• HP Advancestack 100vg Hub-7m (product J2413A)
• HP Advancestack 100vg Hub-14 (product J2415A)

Install an HP 100vg SNMP/Bridge Module (product J2414B) in the back of the 100vg hub. The SNMP/Bridge module bridges 100vg to various 10Mbps technologies through the use of one of the following 10Mbps transceivers which you install in the SNMP/Bridge module:

• HP Advancestack Twisted-Pair Transceiver Module (product J2607A)
• HP Advancestack ThinLAN Transceiver Module (product J2608A)
• HP Advancestack Fiber-Optic Transceiver Module (product J2606A)

Connect the transceiver to your 10Mbps network.

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Q: How do I connect my 100vg network to a 100Base or gigabit network?
For specific details on 100vg integration to a 100Base or gigabit network, refer to the HP 100vg Integration Guide.

You can also use a "multi-homed" PC running an operating system such as Microsoft Windows NT Workstation. By placing an HP 10/100vg PCI LAN Adapter (product J2585B) and either a 100Base or gigabit LAN Adapter card in the PC, you can use the routing feature of the operating system to connect your 100vg network to networks using other technologies.

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