Yealink SIP-T27G Administrator's Guide

General Features
494
Default
0
Web UI
Features > General Information > Hide Feature Access Codes
Accept SIP Trust Server Only
Accept SIP trust server only enables the phones to only accept the SIP message from your SIP server and outbound
proxy server. It can prevent the phone from receiving the ghost calls whose phone number maybe 100, 1000 and
so on. If you enable this feature, the phone cannot accept an IP address call.
Topic
Accept SIP Trust Server Only Configuration
Accept SIP Trust Server Only Configuration
The following table lists the parameters you can use to configure accept SIP trust server only.
Parameter
sip.trust_ctrl <y0000000000xx>.cfg
Description
It enables or disables the phone to only accept the SIP message from the SIP and outbound proxy
server.
Permitted
Values
0-Disabled
1-Enabled, users cannot accept the IP call
Default
0
Web UI
Features > General Information > Accept SIP Trust Server Only
100 Reliable Retransmission
As described in RFC 3262, the 100rel tag is for the reliability of provisional responses. When presented in a Sup-
ported header, it indicates that the phone can send or receive reliable provisional responses. When presented in a
Require header in a reliable provisional response, it indicates that the response is to be sent reliably.
Example of a SIP INVITE message:
INVITE sip:1024@pbx.test.com:5060 SIP/2.0
Via: SIP/2.0/UDP 10.3.6.197:5060;branch=z9hG4bK1708689023
From: "1025" <sip:1025@pbx.test.com:5060 > ;tag=1622206783
To: <sip:1024@pbx.test.com:5060 >
Call-ID: 0_537569052@10.3.6.197
CSeq: 2 INVITE
Contact: <sip:1025@10.3.6.197:5060 >
Authorization: Digest username="1025", realm="pbx.test.com", nonce="BroadWorksXi5stub71Ts2nb05BW", uri-
i="sip:1024@pbx.test.com:5060", response="f7e9d35c55af45b3f89beae95e913171", algorithm=MD5, cnon-
ce="0a4f113b", qop=auth, nc=00000001
Content-Type: application/sdp
Allow: INVITE, INFO, PRACK, ACK, BYE, CANCEL, OPTIONS, NOTIFY, REGISTER, SUBSCRIBE, REFER,
PUBLISH, UPDATE, MESSAGE
Max-Forwards: 70
User-Agent: Yealink SIP-T46G 28.82.0.20

Yealink SIP-T27G Specifications

General

Mounting	Desk/Wall
Handset type	Wired handset
Product type	IP Phone
Product color	Black, Gold
Wall mountable	Yes
Display diagonal	3.66 \
Display resolution	240 x 120 pixels
RJ-9 ports quantity	2
USB 2.0 ports quantity	1
Voice codecs	CNG, G.711, G.722, G.723.1, G.726, G.729, G.729ab, VAD, iLBC
Dual-Tone Multi-Frequency (DTMF) modes	SIP info
Lines quantity	8 lines
Phonebook capacity	1000 entries
Number of VoIP accounts	6
Bluetooth	-
Security algorithms	AES, MD5
Networking standards	IEEE 802.1Q, IEEE 802.1p, IEEE 802.1x, IEEE 802.3af
Ethernet LAN interface type	Gigabit Ethernet
Volume control	Digital
Operating temperature (T-T)	-10 - 50 °C
Operating relative humidity (H-H)	10 - 95 %
Cables included	LAN (RJ-45)
Number of handles included	1 pc(s)
Harmonized System (HS) code	85171800

Weight and Dimensions

Depth	210 mm
Width	265 mm
Height	170.5 mm