Rear Panel; Network Card Leds - Tektronix Z780N - Phaser 780 Color Laser Printer Reference Manual

Rear panel

Connectors
The rear panel of the printer features the host interface connectors:
Bi-directional parallel (high-density connector).
Twisted Pair 10baseT Ethernet connector. RX indicator (green); blinks
while the network card is receiving data. The LED is off steady while no
data is being received. If the LED is on steady, then a problem (probably
hardware) has occurred at the network hub.
SCSI high-density connector (external hard disk drive or optical scanner
only).
With the addition of a network card, the printer can feature either of these groups
of connectors:
ThinNet (100base2) and Twisted Pair (100baseT) Ethernet connectors.
This is Option P1.
LocalTalk connector. This is Option P3.
Unshielded Twisted Pair (10baseT) and shielded Twisted Pair (DB-9)
Token Ring connectors. This is Option P4.

Network card LEDs

The Ethernet network card has four LED indicators:
TX indicator (yellow); blinks while data is transmitted to the host. The
LED is off while no data is being sent.
Twisted Pair (100baseT) and ThinNet (100base2). RX indicator (green);
blinks while the network card is receiving data. The LED is off steady
while no data is being received. If the LED is on steady, then a problem
(probably hardware) has occurred at the network hub.
TP Link. On steady indicates good circuit to nearest port; off indicates
no circuit.
100 MBS. Ethernet speed is 100 MBS when lit.
Note
Do not use both Ethernet connectors at the same time. With a
Ethernet or Token Ring network card installed, the 10baseT port
is disabled.
12 Phaser 780 Color Printer