MyPBX U520 (IP PBX for Your Business)      MyPBX U520 is an enterprise-grade solution designed for offices of up to 500 users, supporting up to 80 concurrent calls. It boasts to have 2 embedded PRI (E1/T1/J1) ports and 16 phone ports for PSTN, ISDN BRI and GSM/UMTS connectivity. Thus U520 couples VoIP with traditional telephone lines offering scalability, high availability, cost saving, and simplified support and maintenance. Support 500 Users Support 80 Concurrent Calls 2 E1/T1/J1 Port Up to 16 Analog Ports Up to 8 GSM/UMTS Ports Up to 8 BRI Ports One RS232 Port Support Call Recording Features Attend Transfer Blind Transfer BLF Support Blacklist CDR (Call Detail Records) Call Forward Call Parking Call Pickup Call Routing Call Transfer Call Waiting Caller ID Conference Define Office Time Dial by Name DISA (Direct Inward System Access) DIDs Distinctive Ringtone DND (Do Not Disturb) Firewall Follow Me IVR (Interactive Voice Response) Intercom/Zone Intercom Multi-language Prompt Music On Hold Music On Transfer MyTwins (Double System) One touch record Phone Provisioning PIN User (PIN Code Control) Paging/Zone Paging Queue Ring Group  Route by Caller ID Skype Integration (Skype Connect) Speed Dial Three Way Calling Voicemail Voicemail to Email Voicemail Forwarding Web Based Control Panel Spy functions (Normal Spy, Whisper Spy, Barge Spy) Specification Users: 500 Concurrent Calls(Max): 80 Voicemail: 3000min (upgradable) Auto-Recording(Add-on): Support Hard Disk: Support 2.5 inch SATA2 (Optional) Interface: Two E1/T1/J1 ports (Support PRI,MFC R2,SS7) Up to 16 Analog Ports (FXO/FXS) Up to 8 GSM Ports (850/900/1800/1900MHz) Up to 8 UMTS Ports (900/2100 or 850/2100MHz) Up to 8 BRI Ports One RS232 Port LAN: 1 (10/100Mbps) WAN: 1 (10/100Mbps) USB: 1 (USB2.0) Audio In/Out: Supported Size: 438x280x44 mm (1U Rack-Mount) Weight: 3.4kg Power Supply: AC100-240V 50/60Hz (15A MAX) Protocol: SIP(RFC3261), IAX2 Transport Protocol: UDP,TCP,TLS, SRTP Codec: G711, GSM, SPEEX, G722, G726, G729A, ADPCM, H261, H263, H263p, H264, MPEG4. DTMF: Inband, RFC2833, SIP INFO Echo Cancellation: Supported LED: Red for FXO/GSM/UMTS, Orange for BRI, Green for FXS. Network: Static IP, PPPoE, DHCP, Firewall, VLAN, DDNS, QoS, DHCP Server, OpenVPN Multiple Languages Support: Chinese, Dutch, English, French, German, Hebrew, Korean, Italian, Polish, Portuguese, Romanian, Russian, Spanish, Thai, Turkish Internal Construction