ST-500 Features
ST-500 INSTALLATION GUIDE
Page 1-3
1.1.1
LANVIEW LEDs
The ST-500 transceiver has five LANVIEW LEDs that monitor network
activity (transmit, receive and collision present), power status, and heart-
beat (SQE) test status. These LEDs are described in Table 1-1. They
serve as a useful tool to quickly diagnose physical layer problems.
1.1.2
Heartbeat (SQE) Test
The ST-500 transceiver supports the Heartbeat (SQE) test. An internal
switch is provided to enable or disable the heartbeat (SQE) test. The sig-
nal quality error (SQE) feature is used by some hosts to verify collision
signal path.
When the SQE test is enabled, the transceiver sends a 10-MHz burst on
the collision lead after transmissions. The burst must begin between 600
and 1600 ns after the end of the packet and must last for 500 to 1500 ns
(see Figure 1-2). The times are measured at the transceiver connector.
There is no collision test signal when just receiving.
Table 1-1. LANVIEW LEDs
LED
DESCRIPTION
PWR
Power - On when the transceiver is receiving power
from the attached node.
SQE
Signal Quality Error Test - On if the Heartbeat (SQE)
test is enabled.
XMT
Transmit - On during the transmission of packets from
the host.
RCV
Receive - On to indicate traffic on the network.
CLN
Collision Present - On when a collision is detected by
the transceiver.
