User manual

Chapter 1

Overview

CentreCOM Multiport Repeaters

AT-3004SL 4 Port with

One AUI

AT-3008SL 8 Port with

One AUI

The CentreCOM Multiport Repeaters are designed to connect up to 8

Ethernet/IEEE 802.3 thin (10BASE2) network segments. In addition to the

thinnet interfaces, a single IEEE 802.3 Attachment Unit Interface (AUI) is

provided for attachment to external transceivers. In this way, these

repeaters allow for connection between the different media (thick or thinnet

coaxial, ﬁber optic and twisted pair) with the choice of the appropriate

transceiver.

With each BNC equipped interface, a 50

Ω

internal cable termination is

provided via an externally accessible switch. This feature enables the thinnet

cable to attach directly to the repeater interface, thus eliminating the need

for a T-connector and terminator.

The AT-3004SL and AT-3008SL provide 4 and 8 BNC interfaces respectively,

and a single IEEE 802.3 AUI, which provides easy attachment to the media.

The CentreCOM Multiport Repeaters provide packet regeneration, which

results in a higher performance network. Packet regeneration includes

regenerating preamble, retiming of the data packets, and extending collision

fragments to ensure collision enforcement.

Fault protection is provided by the CentreCOM Multiport Repeaters in 2

distinct ways. First, each segment will automatically disconnect itself when

32 consecutive collisions occur on the same segment. Second, jabber

protection will automatically insert an idle state (10

s duration) for packets

over 5 ms, but less than 20 ms in length.

Network diagnostics are provided on the front of the CentreCOM Multiport

Repeaters with three LEDs for each network segment. Packet “Receive” and

“Collision” are displayed, aiding in troubleshooting each segment. Segment

“On Line” is also displayed to aid in fault isolation, which together with a

segmentation switch, provide a manual partitioning capability for each

segment.