Yealink SIP-T48G Administrator's Guide

Administrator’s Guide for SIP-T2 Series/T19(P) E2/T4 Series/CP860 IP Phones
844
The call cannot be set up successfully.
User A Proxy Server User B
F1. INVITE B
F2. INVITE B
F3. 180 Ringing
F4. 180 Ringing
F8. 200 OK
F7. 200 OK
F5. CANCEL
F6. CANCEL
Step
Action
Description
F1
INVITE—User A to Proxy
Server
User A sends an INVITE message to a
proxy server. The INVITE request is an
invitation to User B to participate in a
call session.
In the INVITE request:
 The IP address of User B is inserted
in the Request-URI field.
 User A is identified as the call
session initiator in the From field.
 A unique numeric identifier is
assigned to the call and is inserted
in the Call-ID field.
 The transaction number within a
single call leg is identified in the
CSeq field.
 The media capability User A is
ready to receive is specified.
 The port on which User B is
prepared to receive the RTP data is
specified.
F2
INVITE—Proxy Server to User
The proxy server maps the SIP URI in the
To field to User B. Proxy server forwards

Yealink SIP-T48G Specifications

General

Expansion module support	Yes
Handset type	Wired handset
Product type	IP Phone
Product color	Black
Volume control	-
Display diagonal	7 \
Display resolution	800 x 480 pixels
Lines quantity	- lines
Phonebook capacity	1000 entries
Number of VoIP accounts	6
AC adapter input voltage	100 - 240 V
Number of handles included	1 pc(s)

Weight and Dimensions

Width	266 mm
Height	185 mm