Yealink T27P Administrator's Guide

Appendix
577
The following figure illustrates a successful call setup and call hold. In this scenario, the
two end users are User A and User B. User A and User B are located at Yealink SIP IP
phones.
The call flow scenario is as follows:
1. User A calls User B.
2. User B answers the call.
3. User A places User B on hold.
User A Proxy Server User B
F1. INVITE B
F2. INVITE B
F7. ACK
F8. ACK
F3. 180 Ringing
F6. 200 OK
F5. 200 OK
F4. 180 Ringing
F12. 200 OK
F9. INVITE B (sendonly)
F10. INVITE B (sendonly)
F11. 200 OK
F14. ACK
F13. ACK
No RTP packets being sent
2-way RTP channel established

Yealink T27P Specifications

General

Wall Mountable	Yes
Local Phonebook	1000 entries
Bluetooth	No
Wi-Fi	No
Gigabit Ethernet	No
Display	3.66" 240x120 pixel graphical LCD with backlight
Audio Features	HD voice, Full-duplex speakerphone
Network	Dual-port 10/100 Ethernet switch
Protocols	SIP v1 (RFC2543), v2 (RFC3261)
Power	IEEE 802.3af PoE
Connectivity	2 x RJ45 10/100M Ethernet ports
Voice Codecs	G.711(A/μ), G.722, G.723, G.729AB, G.726
EHS	Supports EHS with Plantronics headsets
Headset Port	Yes
Power Adapter	5V DC (optional)