AT&T SynJ SB67158 DECT 6.0 4-Line Corded/Cordless Small Business Phone System with Answering System,Black/silver
Brand: AT&T
Color: Black/silver
Refer the User manual and Troubleshooting steps below
DECT 6.0 Technology
1- to 4-Line Capability. Compatible with TL7600 cordless headset, compatible with TL7800 cordless headset
DSL Subscribers may need to us a DSL Filter