Provides interface for 8 digital stations and 2 analog stations- Also provides interface for:- Music-on-Hold or Background Music source- External paging Zone- Equipped with 4 8-conductor interface jacks.- 2 for 8 digital stations- 1 for 2 analog stations or Doorboxes- 1 for Music-on-Hold/Background Music input, and External Paging Zone output, and 2 relay circuit connections.- The above relay circuits are available for:- Door-strike control, when analog ports are used for Doorboxes- Control for Music-on-Hold or Background Music source- Control of External Paging Equipment- Installs only in universal slots 1-3 of Main or Expansion Chassis.- Allows addition of 1 3-Port CO Trunk Daughter Board 3COIDB or 1 PRI Daughter Board 1PRDB.- Maximum 3 per Main or Expansion Chassis.- Maximum 9 per system.