U520是企業級解決方案，專為需要多達500個用戶和80個並發呼叫的企業而設計。 它為FXO，FXS，GSM，CDMA，UMTS，ISDN BRI提供16個電話端口，為企業用戶提供可擴展性，成本節約和簡化管理。

Specification   Features Users 500 Concurrent Calls (Max) 80 Analog Ports (Max) 16 GSM Ports (Max) 8 UMTS Ports (Max) 8 BRI Ports (Max) 8 E1/T1/J1 0/1/2 LAN 1 10/100/1000Mbps WAN 1 10/100/1000Mbps VoIP Trunks 128 IVR 64 Voicemail Default 3000 min (upgradable) Protocol SIP (RFC3261), IAX2 Transport Protocol UDP, TCP, TLS, SRTP Audio Codec G711 (alaw/ulaw), G722, G726, G729A, GSM, Speex, ADPCM Video Codec H263, H263P, H264, MPEG4 DTMF In-band, RFC2833, SIP INFO IP Services DDNS, DHCP, Firewall, OpenVPN, PPPoE, QoS, Static IP, Static NAT, Static Route, STUN, VLAN One Touch Record (Manual) Support Call Recording (Auto) Support Redundancy Support MyTwins Support Audio In/Out – T.38 Fax Support SMS to Mail/Mail to SMS Support Add-ons Support Hard Disk 2.5 inch SATA2 USB 1 TF Card Slot – Dimensions (L × W × H) (mm) 440 × 280 × 44 Weight 3.4 kg Power AC 100-240V (DC 12V 5A)   Flow Chart    Attended Transfer Blacklist Blind Transfer BLF Support Call Back Call Detail Records Call Forwarding Call Pickup Call Routing Call Waiting Caller ID Conference Define Business Hours Dial by Name DISA (Direct Inward System Access) Distinctive Ringtone DNIS Do Not Disturb Fax to Email Firewall Follow me IP Blacklist LDAP IVR (Interactive Voice Response) Intercom/Zone Intercom Mobility Extension Music on Hold Paging/Zone Paging Phone Provisioning PIN User Queue Ring Group Skype Integration Speed Dial Spy Functions Three-way Calling Video Calls Voicemail Voicemail to email Web-based control panel    | mypbx |  Mypbx hk | ipphone hk | ip phone hk | ipphone hk  | yeastar |  yeastar hk  | yealink |  yealink hk | | yealink ip phone  hk | grandstream | grandstream hk |phone system solution | voip solution | mypbx solution |  | ipphone solution | pbx solution |  | call canter hk | call manager  hk | voip system  hk | voip phone hk | sip phone hk | sip ip phone  hk |   | voip system hk | telephone system hk | video telefono grandstream | video conference | video conference system |  | zoom video conference | zoom meeting | zoom hk | | contact center hk | phone center hk | videophone system | video telephone | voip center | ippbx | ip pabx |  | crm system hk | crm manager hk | crm solution | contact solution | ip telephone | conference video solution | | intimate system  | pa system | Broadcast system |  | 客戶關係管理 | 客戶關係管理 香港 | 呼叫中心  香港 | 客服中心系統  香港 | 電話系統 香港 | 網絡電話系統 香港 |  | 網絡電話 香港 | 聯絡中心系統 香港 |視像會議 | 視像會議系統 | 視頻會議 | zoom會議 | zoom 視像會議 |  | crm 系統 | 香港 crm | 管理系統 香港 | 廣播系統 | 廣播系統 香港 | 客戶中心解決方案 | pbx解決方案 | 客戶聯絡解決方案|