Cabletron Systems SEH-34 - Manual (Page 10)

INTRODUCTION
Page 1-3
You can stack together up to five SEH hubs using Cabletron Systems’
external HubSTACK Interconnect cables. If you want to add
management to the stack, Cabletron Systems offers the MicroMMAC
and the SEHI intelligent hubs. You can stack up to four SEHs with
one intelligent hub. Stackable configurations let you maintain only
one IEEE repeater hop while providing up to 130 Ethernet ports.
The SEH-22/24 and SEH-32/34 are functionally identical with the
exception of the network ports:
• SEH-22 , 12 RJ45 network ports and one EPIM port.
• SEH-24 , 24 RJ45 network ports and two EPIM ports.
• SEH-32 , one 50 pin Champ connector, providing 12 twisted
pair segments, and one EPIM port.
• SEH-34 , two 50 pin Champ connectors, providing 24 twisted
pair segments, and two EPIM ports.
1.4 SEH FEATURES
Repeater Functionality
The SEH fully conforms to the IEEE 802.3 Repeater, AUI, and
10BASE-T specifications, and provides the flexibility to connect
networks using IEEE 802.3, Ethernet Version 1 or Version 2
equipment. The SEH transmits re-timed data packets, regenerates the
preamble, extends fragments, and arbitrates collisions.
The SEH automatically partitions problem segments, and reconnects
repaired segments to the network. This feature minimizes the impact
on network operation by isolating the problem segment. Only devices
on the problem segment are affected. When the problem is solved, the
SEH automatically reconnects the isolated segment to the network.
Polarity Detection and Correction
Each twisted pair port on the SEH incorporates a Polarity Detection
and Correction feature that allows the SEH to pass data regardless of
the polarity of the twisted pair segment’s receive link. We do not
recommend operating in this condition. If you discover this condition,
remove the segment from the network and wire it correctly. This
reduces the potential for problems if equipment changes are made.