User Number (SIP): Up to 100 internal subscribersCalls at the same time: Maximum 25Voice message: 3000 minutes flash memoryAuto-Recording (Add-on): SupportsAudio In / Out: SupportsSupported interfaces: up to 16 analog (FXO / FXS), up to 8 GSM, up to 8 UMTS, up to 8 BRIsRegistration of calls and writ..