26
YORK INTERNATIONAL
FORM 450.20-N20 (702)
MAINTENANCE
SECTION 4
MAINTENANCE
LEDs
The Universal LINCs are equipped with LEDs to aid
in troubleshooting operation and communications.
Status LED
A red Status LED indicates operating condition.
There are three operational states for the Status LED.
ON – The device is on and operating normally.
FLASHING – The Node switch is set to 0, which
is an invalid address.
OFF – The device has failed or has lost power.
NOTE: The Status LED flashes once
whenever the device type is changed to
indicate reset.
Port LEDs
Each port has two Comms LEDs to signify the
module is receiving (RX) or transmitting (TX) data.
The RX LED is green and the TX LED is red.
The TX LED indicates that data is transmitting across
the LAN to another controller or device. Since the
ISN software requires an acknowledgement anytime
communication is sent, a TX flash will be followed
by an RX flash. The RX flash signifies the receipt of
the acknowledgement. However, this is not a one-to-
one ratio.
When operating as a repeater at 19.2 kbaud, every
RX LED flash at one port should be followed by a
corresponding TX LED flash at the opposite port. At
50 kbaud, this does not apply because of the filtering
that occurs.
