1-6 lines; 8-32 extensions Caller ID Password Programming Boss/Secretary Function Do Not Disturbance Power Failure Transfer Multiple Communication channels Call Duration Control Conferences (1CO.line and 2 Extensions) Remote Program OGM recording for Auto-Attendant mode with DISA optional Extension number changeable Out-going call restriction class optional for Extension Different Ringing for Internal & External call 208A,308A,312A,316A can compatible with Door bell & Door opener