Compact Media Converter
Installation Guide
LGC5134A — LGC5135A
About L1 Gigabit Media Converters
L1 Gigabit Compact Media Converters
are IEEE 802.3 and provide a single-
conversion between 1000Base-TX twisted pair and 1000Base-SX multi-mode
or 1000Base-LX single-mode fiber. L1 Gigabit is available with one RJ-45 con-
nector for the twisted pair port and an SC connector for the fiber port.
L1 Gigabit is a 1U high, standalone unit that includes diagnostic LEDs for each
port and a universal (100/240 VAC) power supply.
L1 Gigabit TX/850SXMM-SC — 1000Base-T twisted pair/1000Base-SX 850 nm multi-mode
fiber; one RJ-45 connector and one pair SC (LGC5134A) connectors.
L1 Gigabit TX/LX SM/PLUS-SC — 1000Base-T twisted pair/1000Base-SX 13100 nm single-
mode fiber; one RJ-45 connector and one pair SC (LGC5135A) connectors.
Installing L1 Gigabit
L1 Gigabit comes ready to install. The only adjustments that may need to
be made come after installation. To install L1 Gigabit, first make sure that the
unit is placed on a suitable flat surface. Attach the cables between the L1
Gigabit and each device that will be interconnected, then plug the unit into a
reliable, filtered power source.
Configuring L1 Gigabit
Once installed, L1 Gigabit can be configured for
the following features: Duplex Mode, Master/Slave
Mode and FiberAlert.
D I P S
S
W I T C H
E T T I N G S
L1 Gigabit features an 8-position DIP switch for
configuring the unit. The switch is accessed through
a cut-out in the bottom of the unit. The following
table provides simplified definitions of the function of each switch.
S
F
WITCH
UNCTION
1 1
Duplex Mode (ON: Half-Duplex, OFF: Full-Duplex)
2 2
Master/Slave Mode (ON: Master, OFF: Slave)
4 4
FiberAlert
3 3 , , 5 5 - - 8 8
Factory Use Only — DO NOT CHANGE
1
Gigabit
D
U P L E X
The Duplex mode settings of the L1 Gigabit converter are used with Auto-
Negotiation. The default Duplex mode for L1 Gigabit is Full-Duplex. In this
mode, Full-Duplex is advertised during Auto-Negotiation. To make the unit
operate in Half-Duplex, simply move DIP switch 1 from the OFF to the ON
position. This will allow only Half-Duplex to be advertised during Auto-
Negotiation. The Auto-Negotiation takes place on the twisted-pair interface
only. When the twisted-pair interface is resolved, the configuration will be
encoded into the fiber side. No auto-negotiation takes place on the fiber side.
As a result, it is usually best to disable Auto-Negotiation on the remote fiber
end. Since most gigabit networks run at Full-Duplex, it is recommended to set
the remote fiber end to Full-Duplex.
M
/ S
A S T E R
This feature determines which clock will be used between the L1 Gigabit and
the device it is connected to (a switch, NIC, or another L1 Gigabit, etc.). Master
mode is the default setting, where L1 Gigabit's clock is used. To change this to
the Slave setting, move DIP switch 2 to the OFF position. L1 Gigabit will then
receive and use the clock of the other connected device.
NOTE: The Master/Slave mode is only valid for the twisted pair link.
R
B
E S E T
If your unit is running and you change either the Duplex Setting or Master/
Slave mode, you will need to reset your unit before these changes take effect.
The Reset button located on the front faceplate can accomplish this. To reset
the unit, take a slender, non-conductive object, about the width of a paper clip,
insert it into the hole in the chassis, and press the Reset button inside. Please
observe proper ESD procedures when resetting your chassis. Note that power
cycling the unit (i.e. removing the power cord and then reconnecting it) will
also reset L1 Gigabit.
Negotiation and L1 Gigabit
S1
OFF/ON
L1 Gigabit will negotiate between Master and Slave mode. To avoid conflicts
1
FDX/HDX
2
with devices connected to L1 Gigabit, it senses which mode is appropriate and
SLV/MSTR
3
RESERVED
will then choose that mode. L1 Gigabit also negotiates between Half- and Full-
4
FA
duplex. Typically, when L1 Gigabit is connected to a NIC or switch, it functions
5
RESERVED
as a Master, as the NIC and switch auto-negotiate and determine which mode
6
RESERVED
will not cause conflict. The L1 Gigabit should drop down to Slave mode
7
RESERVED
when connected to a switch or other multi-port device. When connected to
RESERVED
8
another L1 Gigabit, there is a period of time where, while negotiation is taking
place, errors may be seen. After a short period of time, the device returns to
normal operation.
D
EFAULT
O O F F F F
O O N N
O O F F F F
N N / / A A
M
O D E
M
L A V E
O D E
O
U T T O N
P E R A T I O N
2
About FiberAlert
FiberAlert is an advanced troubleshooting feature that helps locate "silent fail-
ures" on your network. However, it is vital that you understand exactly how
FiberAlert works, and how it will react in your network configuration, before
attempting to install the enclosed unit.
Installing modules without understanding the effects of FiberAlert
can cause perfectly functioning units to appear flawed or even dead.
W
I
F
A
?
H A T
S
I B E R
L E R T
Local Site
FiberAlert minimizes the problems
XMT
associated with the loss of one strand of
RCV
fiber.
If a strand is unavailable, the
LED
Compact Media Converter, at the receiv-
er end, notes the loss of link.
The
LED OFF = Broken Link
device will then stop transmitting data
Black Box product with FiberAlert Enabled
and the link signal until a signal or link
Local Link LED is OFF indicating a break in the fiber loop
pulse is received. The result is that the
link LED on BOTH sides of the fiber connection will go out indicating a fault
somewhere in the fiber loop. Using FiberAlert, a local site administrator is noti-
fied of a fault and can quickly determine where a cable fault is located.
A A u u t t o o C C r r o o s s s s F F e e a a t t u u r r e e f f o o r r T T w w i i s s t t e e d d P P a a i i r r C C o o n n n n e e c c t t i i o o n n s s
The twisted pair port of the L1 Gigabit includes AutoCross, a feature which
automatically selects between a crossover workstation or pass-through/repeater
hub connection depending on the connected device.
Installation Troubleshooting
• During installation, first test your fiber and twisted pair connections with
FiberAlert disabled. Then enable FiberAlert, if desired, just before final
installation. This will reduce the feature's interference with testing.
• FiberAlert should only be enabled on one side of a media conversion.
Enabling it on both sides would keep both transmitters off indefinitely.
• To test L1 Gigabit by itself, you must have an appropriate fiber patch
cable. First, connect L1 Gigabit to the twisted pair device with a twisted
pair cable. Next, loop a single strand of fiber from the transmit port to
the receive port of your media converter. Finally, verify that you have
both twisted pair and fiber link on your media converter.
•
Make sure you are using the appropriate twisted pair cable (i.e. crossover
or pass-through). Gigabit Ethernet requires Cat-5 cabling and patch cords.
3
Cable Break
Remote Site
RCV
XMT
LED
Remote Site stops transmitting
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