Yealink SIP-T52S Administrator's Guide

Configuring Advanced Features
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6. If you use outbound proxy servers, do the following:
1) Select Enabled from the pull-down list of Enable Outbound Proxy Server.
2) Configure parameters of outbound proxy server 1/2 in the corresponding fields.
You must set the port of outbound proxy server to 0 for NAPTR, SRV and A queries.
7. Click Confirm to accept the change.
Server Domain Name Resolution
If a domain name is configured for a server, the IP address(es) associated with that domain
name will be resolved through DNS as specified by RFC 3263. The DNS query involves NAPTR,
SRV and A queries, which allows the IP phone to adapt to various deployment environments.
The IP phone performs NAPTR query for the NAPTR pointer and transport protocol (UDP, TCP
and TLS), the SRV query on the record returned from the NAPTR for the target domain name
and the port number, and the A query for the IP addresses.
If an explicit port (except 0) is specified, A query will be performed only. If a server port is set to
0 and the transport type is set to DNS-NAPTR, NAPTR and SRV queries will be tried before
falling to A query. If no port is found through the DNS query, 5060 will be used.
The following details the procedures of DNS query for the IP phone to resolve the domain
name (e.g., yealink.pbx.com) of working server into the IP address, port and transport protocol.
NAPTR (Naming Authority Pointer)
First, the IP phone sends NAPTR query to get the NAPTR pointer and transport protocol.
Example of NAPTR records:
order pref flags service regexp replacement

Yealink SIP-T52S Specifications

General

Touchscreen	-
Display diagonal	2.8 \
Backlight display	Yes
Display resolution	320 x 240 pixels
Lines quantity	16 lines
Phonebook capacity	1000 entries
Number of VoIP accounts	12
AC adapter input voltage	100 - 240 V
Bluetooth version	2.1+EDR
Security algorithms	802.1x RADIUS, HTTPS, MD5
Ethernet LAN interface type	Gigabit Ethernet
USB 2.0 ports quantity	1
Ethernet LAN (RJ-45) ports	2
Mounting	Desk/Wall
Handset type	Wired handset
Product type	IP Phone
Product color	Black
Voice codecs	G.722, G.723, G.723.1, G.726, OPUS, iLBC
Volume control	Digital
Operating temperature (T-T)	-10 - 40 °C
Operating relative humidity (H-H)	10 - 95 %
Cables included	LAN (RJ-45)
Number of handles included	1 pc(s)
Front camera	No
Operating system installed	Linux

Weight and Dimensions

Depth	212 mm
Width	211.6 mm
Height	166.8 mm