Communicator e3000 MPE/iX Release 7.0 Express 1 (Software Release C.70.01) (30216-90328)

Chapter 3 51
New Networking
The PCI 100Base-T Link Product
When choosing the number of LAN cards, the customer should be aware that use of the
e3000 as a high-speed gateway between LAN networks is not supported.
Crossover cable usage with DTC and PCI 100Base-T link
The 10/100Base-TX link (add-on or Core I/O) in the N-Class and A-Class HP e3000
systems may be used to drive a single DTC in 10Base-T mode, via a crossover LAN cable.
When there is a need to interconnect a single DTC and server, this provides connectivity
similar to older coax ThinLAN.
The DTC must attach an external 10Base-T transciever (28685B or equivalent, orderable
separately) to its AUI port; the DTC recognizes the transciever after cycling power. In
NMMGR, the host link must be configured for speed=10Mbps, full duplex=No, and
autonegotiation=No. Standard 10Base-T cable length limitations also apply (in this case
100m or less).
10/100Base-TX technology utilizes only two of the four twisted wire pairs available at an
RJ-45 cable connector. A crossover cable differs from a straight-through LAN patch cable,
because the two active pairs (pins 1-2 and 3-6) at one end connect to the opposite pair (3-6
and 1-2) at the other end. Such “crossed” wiring can sometimes be verified by visually
inspecting the different wire colors through the clear plastic plug: when placed
side-by-side with identical orientation, if both ends of the cable have the same left-to-right
wire color sequence, this is a straight-through patch cable.
10Base-T crossover LAN cables are available in various lengths from most computer
supply stores, or from HP (C7539A is 2m long and C7538A is 7m). Coax ThinLAN cables
are no longer included with N-Class and A-Class HP e3000 systems (one straight-through
patch cable is included instead).