Excelsus Z-300TJ DSL Filter - Pulse DSL filters Data Protection - Isolates telephone impedances changes from DSL equipment Voice Protection - Isolates DSL band frequencies from voice band equipment Provides a DSL convenience jack for connecting a DSL modem or HPN device Compatible with all major DSL standards including ADSL, ADSL2+, VDSL, and VDSL2 Compatible with Caller ID, facsimile and metallic loop testing