TONNET DCS 500 PBX 
 Maximum capacity: 504 (mining free slot design) 
 Outside the maximum number of gates: 200 
 Inside the maximum number of gates: 504 
 DECT can be upgraded to wireless communication systems 
 Can be upgraded to SIP IP network communications system 
 Can be upgraded to a nurse call intercom system 
 Can be upgraded to a residential building intercom system 
 Can be upgraded to the campus safety monitoring system (with CCTV) 
 Caller ID amplified external dual function (FSK & DTMF) 
 Amplified E1/T1/E & M / ISDN PRI 
 ARS / LCR routing