METRObility Optical Systems 2152-DJ-01, 2152-AY-01, 2152-77-01 manual Link Loss Return LLR Switch

LLCF LLR1LLR2

OFF

ON

PWR

DC INPUT/5VDC

		“twister” ™2152
	1000BASE-LX	1000BASE-SX
		PWR
TX	RX TX	RX
	LINK	LINK

Port 2 Port 1

CLCF LLR2 LLCF LLR1LLR2 LLCF LLR1LLR2

OFF or OFF or ON

ON ON OFF

DIP switches (2152 TX-FX) DIP switches (2152 FX-FX) DIP switches (all others)

NOTE: The ON/OFF positions are not the same on all units.

By default, all DIP switches are disabled.

Link Loss Return (LLR) Switch

The Metrobility “twister” incorporates Link Loss Return functionality as an aid in troubleshooting remote fiber connections. When LLR is enabled on a port, loss of the receive (RX) link at the port disables the transmit (TX) link on the same port. LLR is set independently on each fiber port.

LLR1 enables/disables Link Loss Return on Port 1, and LLR2 enables/ disables it on Port 2. To enable Link Loss Return, set the LLR switch to the ON position. Set the switch OFF to disable the function. The unit is shipped with LLR disabled. For more information, refer to Link Loss Return in the User Guide section of this manual.

Link Loss Carry Forward (LLCF) Switch

On the fiber-to-fiber repeaters, Link Loss Carry Forward is provided as an additional aid for troubleshooting remote connections. If LLCF is enabled and the “twister” loses link on one of its receive ports, LLCF inhibits the transmit link out the opposite port.

For example, if LLCF is enabled and the “twister” fails to detect link on Port 2, the “twister” will not transmit link pulses out of Port 1. In doing this, LLCF provides a way to extend the link loss indication beyond a single segment.

Gigabit “twister” and SONET “twister” 7