Nortel 5399 Hardware Installation Manual page 29

Port Usage LEDs
WAN Interface Ports
The Port Usage LEDs, labelled 25%, 50%, 75%, and 100%, indicate the
approximate percentage of B channels that are being utilized. There are
two sets of Port Usage LEDs, one set for each WAN Port. These LEDs
are normally green. If all available B channels are in use, they turn amber
until at least one call disconnects.
The two WAN interface ports provide access to Channelized T1,
Channelized E1, or ISDN PRI lines. The WAN Interface ports come with
8-pin, RJ48C jacks for attaching the T1, E1 or ISDN cable connectors.
Nortel Networks 5399 Access Switch Hardware Installation Guide
Chapter 1 Introduction
1-11