Yealink SIP-T27G Administrator's Guide

General Features
500
After configuration, you can check the configuration file version information at the path: Menu > Status
> Phone > MAC Version (phone user interface) or Status > Status > Version > MAC Version (web
user interface).
Permitted
Values
String
Default
Blank
Supported
Devices
All phones except T48G, T46G, T42G, T41P and T29G
Parameter
features.custom_version_info <y0000000000xx>.cfg
Description
It configures the version information of the CFG configuration file.
After configuration, you can check the configuration file version information at the path: Menu > Status
> CFG Version (phone user interface) or Status > Status > Version > Configuration Version (web
user interface).
Permitted
Values
String
Default
Blank
Supported
Devices
T48G, T46G, T42G, T41P, T29G
Media Loopback
The SIP RTP media loopback can be used to make test calls to verify the media path between the phone and
server.
RTP packets are looped back toward the source device. In a voice loopback call, an echo is heard at the device ori-
ginating the call.
For more information on media loopback, refer to RFC 6849.
Topic
Media Loopback Configuration
Media Loopback Configuration
The following table lists the parameters you can use to configure media loopback.
Parameter
sip.loopback.enable <y0000000000xx>.cfg
Description
It configures the loopback role for the phone.
Note: After the phone accepts the loopback call, the mute feature will be automatically activated on
the phone.
Permitted
Values
0-Loopback-Mirror, the server initiates a loopback call, and the phone accepts the call and mirrors
(echoes) all received media back to the server.
1-Loopback-Source, the phone can initiate a loopback call as a media source or receive a loopback
call as a loopback mirror.
Default
0
Parameter
sip.loopback_type <y0000000000xx>.cfg
Description
It configures the media loopback type.
Permitted
Values
1-rtp-media-loopback, the packet received by loopback mirror is re-encoded based on the SDP nego-
tiation. The re-encoded content is returned to the loopback source as an RTP packet with payload
type corresponding to the re-encoding format.

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