Features: 1. When either of the 4G phone and the VOIP phone is connected, the other party can also call in 2. Phone book, one-key dialing, SIP account, hands-free calling, incoming and outgoing call query, AP hotspot, super long standby time 3. 2.4-inch color screen design, intelligent and more friendly user interface 4. Super CPU, quad-core A53, creating a smoother operating experience 5. Support the three major operators of China Mobile, China Telecom and China Unicom, and 4G full Netcom 6. Can register 2 SIP accounts, support account switching 7. Support 3-party audio conference, you can add members to join at any time, making communication more convenient 8. Call transfer: When you make a call, click the option button to select transfer, and you can transfer the call with one click, which is fast and worry-free 9. Call hold: During the call, if it is inconvenient, you can press the hold button, the call will not end, press the hold button again, and the call will continue 10. 3 groups of fast dialing, 8 programmable function keys that can be customized, frequently used numbers can be set, one-key call out, convenient for office and elderly use 11. Support Volte high-definition calls, you can imagine high-definition sound quality without the microphone close to the ear 12. One-button hands-free calling, free your hands, chat freely, and do whatever you want 13. Support automatic answering of calls, bid farewell to the trouble of not having time to answer calls when busy 14. Do-not-disturb mode can be set, when someone calls in, it will not ring, but the call information will still be recorded 15. Detailed incoming and outgoing call records, convenient for you to check at any time 16. Turn on the WIFI function, you can quickly and easily find the WIFI signal 17. Built-in rechargeable lithium battery, convenient for mobile office anytime and anywhere, avoiding the trouble of plugging in all the time. 18. Durable, strong power, rechargeable battery, recycling 19. VOIP/SIP compatibility, compatible with multi-platform manufacturers Parameter: 1. LCD display: 2.4 inch color screen 2. WIFI AP: 802.11b/g/n2.4G 3. DTMF function: RFC 2833, SIPINFO 4. Network protocol: HTTP/TR069/RTP/SRTP 5. Power supply mode: USB charging / built-in lithium battery 6. Battery capacity: 1000mah 7. Scope of application: home, office, medical care, hotel, catering, transportation, etc. 8. Size: 20 x 18.2 x 8cm 9. Weight: 0.627kg Audio function: 1. G.722/G.729/AMR/AMRWB/GSM/PCMA/PCMU/SPEEX/ILB/DTMF/ISACWB/OPUS 2 Support high-quality audio calls 3. VAD/CNG/AGC/ANS/AEC SIP function: 1. Support SIP 2.0 (RFC3261) 2. Support 2-way SIP account 3. Support SIP UDP/TCP/TLS Phone function: 1. Add/delete contacts, missed call reminder 2. Do Not Disturb, Auto Answer 3. Call forwarding/busy forwarding/unconditional forwarding