Yealink SIP-T48U Administrator's Guide

Administrator’s Guide for SIP-T2 Series/T4 Series/T5 Series/CP920 IP Phones
495
Supported: 100rel
Allow-Events: talk,hold,conference,refer,check-sync
Content-Length: 302
Topic
100 Reliable Retransmission Configuration
100 Reliable Retransmission Configuration
The following table lists the parameter you can use to configure the 100 reliable retransmission.
Parameter
account.X.100rel_enable
[1]
<MAC>.cfg
Description
It enables or disables the 100 reliable retransmission feature.
Permitted
Values
0-Disabled
1-Enabled
Default
0
Web UI
Account > Advanced > Retransmission
[1]
X is the account ID. For T57W/T54W/T48U/T48S/T48G/T46U/T46S/T46G/T29G, X=1-16; for
T53W/T53/T43U/T42G/T42U/T42S, X=1-12; for T41P/T41S/T27G, X=1-6; for T40P/T40G/T23P/T23G, X=1-3; for T21
(P) E2, X=1-2; for T19(P) E2/CP920, X=1.
SIP Session Timer
SIP session timers T1, T2 and T4 are SIP transaction layer timers defined in RFC 3261. These session timers are
configurable on the phones.
Timer T1
Timer T1 is an estimate of the Round Trip Time (RTT) of transactions between a SIP client and SIP server.
Timer T2
Timer T2 represents the maximum retransmitting time of any SIP request message. The re-transmitting and doub-
ling of T1 will continue until the retransmitting time reaches the T2 value.
Example:
The user registers a SIP account for the IP phone and then set the value of Timer T1, Timer T2 respectively (Timer
T1: 0.5, Timer T2: 4). The SIP registration request message will be re-transmitted between the IP phone and SIP
server. The re-transmitting and doubling of Timer T1 (0.5) will continue until the retransmitting time reaches the
Timer T2 (4). The total registration request retry time will be less than 64 times of T1 (64 * 0.5 = 32). The re-trans-
mitting interval in sequence is 0.5s, 1s, 2s, 4s, 4s, 4s, 4s, 4s, 4s and 4s.
Timer T4
Timer T4 represents that the network will take to clear messages between the SIP client and server.
Topic
SIP Session Timer Configuration
SIP Session Timer Configuration
The following table lists the parameters you can use to configure the SIP session timer.

Yealink SIP-T48U Specifications

General

Handset type	Wired handset
Product type	IP Phone
Product color	Gray
USB 2.0 ports quantity	USB 2.0 ports have a data transmission speed of 480 Mbps, and are backwards compatible with USB 1.1 ports. You can connect all kinds of peripheral devices to them.
Expansion module support	Yes
Ethernet LAN (RJ-45) ports	2
Display diagonal	7 \
Display resolution	800 x 480 pixels
Lines quantity	- lines
Phonebook capacity	1000 entries
Number of VoIP accounts	16
Voice codecs	AGC, AJB, AMR-WB, CNG, G.711, G.722, G.723.1, G.726, G.729ab, VAD, iLBC
Security algorithms	AES, HTTPS, SRTP, TLS
Ethernet LAN data rates	10, 100, 1000 Mbit/s
Ethernet LAN interface type	Gigabit Ethernet
Front camera	-
AC adapter input voltage	100 - 240 V
Operating temperature (T-T)	0 - 40 °C
Operating relative humidity (H-H)	10 - 95 %
Keypad number of keys	29
Number of handles included	1 pc(s)
Harmonized System (HS) code	85171800

Weight and Dimensions

Width	226 mm
Height	185 mm