Yealink SIP-T27G Administrator's Guide

Administrator’s Guide for SIP-T2 Series/T4 Series/T5 Series/CP920 IP Phones
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Description
It configures whether to use audio encryption service.
Permitted
Values
0-Disabled
1-Optional, the phone will negotiate with the other phone what type of encryption to use for the ses-
sion.
2-Compulsory, the phone must use SRTP during a call.
Default
0
Web UI
Account > Advanced > RTP Encryption (SRTP)
Parameter
account.X.srtp_lifetime
[1]
<MAC>.cfg
Description
It configures the lifetime of the master key used for the cryptographic parameter in SDP. The value spe-
cified is the number of SRTP packets.
When the lifetime is set, a re-invite with a new key is sent when the number of SRTP packets sent for
an outgoing call exceeds half the value of the master key lifetime.
Note: Setting this parameter to a non-zero value may affect the performance of the phone. It works
only if “account.X.srtp_encryption” is set to 1 (Optional) or 2 (Compulsory).
Permitted
Values
Integer greater than or equal to 0
0-the master key lifetime is not set.
1 to 1024-the master key lifetime is 1024.
1025 to 2^48-the master key lifetime is the configured value.
A value greater than 2^48-the master key lifetime is 2^48.
Default
0
Parameter
account.X.srtp.unencrypted_rtp.enable
[1]
<MAC>.cfg
Description
It enables or disables the phone’s capability to include unencrypted RTP streams in SDP offers when
using SRTP.
Note: It works only if “account.X.srtp_encryption” is set to 1 (Optional) or 2 (Compulsory).
Permitted
Values
0-Disabled
1-Enabled, the phone offers both encrypted and unencrypted RTP streams (Unencrypted RTP
streams carry UNENCRYPTED_SRTP session parameters) in SDP offers. After a successful nego-
tiation, whether the RTP stream is encrypted or not depends on the SDP answer.
Default
0
Parameter
account.X.srtp.unencrypted_rtcp.enable
[1]
<MAC>.cfg
Description
It enables or disables the phone’s capability to include unencrypted RTCP streams in SDP offers
when using SRTP.
Note: It works only if “account.X.srtp_encryption” is set to 1 (Optional) or 2 (Compulsory).
Permitted
Values
0-Disabled
1-Enabled, the phone offers both encrypted and unencrypted RTCP streams (Unencrypted RTCP
streams carry UNENCRYPTED_SRTCP session parameters) in SDP offers. After a successful nego-
tiation, whether the RTCP stream is encrypted or not depends on the SDP answer.
Default
0

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