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2. Classic Slave•  Classic Slave is the designation of the second FX in a two-inverter, split-phase system that produces 
240 VAC without using an FW-X240 Auto Transformer. 
•  This FX is plugged into Port 02 of the HUB.
OB Slave L1 and OB Slave L2 designations are used in OutBack Parallel Stacking or OutBack Series/
Parallel stacking
3. OB Slave L1•  In an OutBack Parallel single-phase system, all the Slave FXs on a single 120 VAC leg are designated 
OB Slave L1. 
•  In an OutBack Series split-phase system, which will include an FW-X240 or PSX-240 Auto Transformer, 
any FX that runs in parallel to the Master FX is designated OB Slave L1.  These FXs must be plugged 
into the lowest HUB Ports.
•  The OB Slave L1 Stacking is typically used for an entirely o -grid application such as a cabin that 
does not require 240 volts.
4. OB Slave L2•  In an OutBack Series split-phase system, any Slave FX that runs in series with the Master FX is 
designated OB Slave L2. 
5. 3ph Master•  In 3-phase stacking, the Master FX is designated as 3ph Master. 
3ph Master and 3ph Slave designation are used in OutBack 3-phase stacking.
6. 3ph Slave• In 3-phase stacking, each of the Slave FXs, which should be plugged into HUB 
Ports 02 (phase B) and 03 (phase C) respectively, is designated as 3ph Slave. 
• When the HUB jumper is set between Port 02 and Port 03, the HUB identifies a 
phase for each Slave FX.
1. 1-2ph Master*
2. Classic Slave
3. OB Slave L1
4. OB Slave L-2
5. 3ph Master
6. 3ph Slave                           *GTVX and GVFX models show “Master” on the screen