Yealink SIP-T38G Administrator's Guide

Appendix
361
Step
Action
Description
requests the call.
F18
INVITE—Proxy Server to User
C
The proxy server maps the SIP URI in the
To field to User C.
F19
180 Ringing—User C to Proxy
Server
User C sends a SIP 180 Ringing
response to the proxy server. The 180
Ringing response indicates that the user
is being alerted.
F20
180 Ringing—Proxy Server to
User A
The proxy server forwards the 180
Ringing response to User A. User A
hears the ring-back tone indicating that
User C is being alerted
F21
200OK—User C to Proxy
Server
User C sends a SIP 200 OK response to
the proxy server. The 200 OK response
notifies the proxy server that the
connection has been made.
F22
200OK—Proxy Server to User
A
The proxy server forwards the SIP 200
OK response to User A.
F23
ACK— User A to Proxy Server
User A sends a SIP ACK to the proxy
server. The ACK confirms that User A
has received the 200 OK response. The
call session is now active.
F24
ACK—Proxy Server to User C
The proxy server forwards the ACK
message to User C. The ACK confirms
that User A has received the 200 OK
response. The call session is now active.
The following figure illustrates a successful call between Yealink SIP IP phones in which
two parties are in a call and then one of the parties transfers the call to the third party
with consultation. This is called attended transfer. In this call flow scenario, the end users
are User A, User B, and User C. They are all using Yealink SIP IP phones, which are
connected via an IP network.
The call flow scenario is as follows:
1. User A calls User B.
2. User B answers the call.
3. User A calls User C.
4. User C answers the call.

Yealink SIP-T38G Specifications

General

Expansion module support	Yes
Ethernet LAN (RJ-45) ports	2
Keypad number of keys	48
Touchscreen	-
Display resolution	480 x 272 pixels
Display number of colors	16.78 million colors
Lines quantity	- lines
Phonebook capacity	1000 entries
Number of VoIP accounts	6
Voice codecs	G.711, G.722, G.723.1, G.726
Bluetooth	No
Security algorithms	802.1x RADIUS, HTTPS, SSL/TLS
AC adapter input voltage	100 - 240 V
AC adapter output voltage	5 V
Power consumption (typical)	4.6 W
Operating relative humidity (H-H)	10 - 95 %
Handset type	Wired handset
Product type	IP Phone
Product color	Black
Compliance industry standards	IEEE 802.3af
Number of handles included	1 pc(s)

Weight and Dimensions

Depth	204 mm
Width	273 mm
Height	42 mm
Weight	1050 g