Yealink SIP-T27P [19/841] Sip ip phone models

Product Overview

request to its destination, as the request URI always specifies the host which is essential.

The port and protocol are not always specified by the request URI. Thus if the request

does not specify a port or protocol, a default port or protocol is contacted. It may be

preferential to use this method when not using an application layer firewall. Application

layer firewalls like to know what applications are flowing through which ports and it is

possible to use content types of other applications other than the one you are trying to

let through what has been denied.

User Agent Server (UAS)

UAS is a server that hosts the application responsible for receiving the SIP requests from

a UAC, and on reception it returns a response to the request back to the UAC. The UAS

may issue multiple responses to the UAC, not necessarily a single response.

Communication between UAC and UAS is client/server and peer-to–peer.

Typically, a SIP endpoint is capable of functioning as both a UAC and a UAS, but it

functions only as one or the other per transaction. Whether the endpoint functions as a

UAC or a UAS depends on the UA that initiates the request.

This section introduces SIP-T48G, SIP-T46G, SIP-T42G, SIP-T41P, SIP-T29G, SIP-T27P,

SIP-T23P/G, SIP-T21(P) E2 and SIP-T19(P) E2 IP phone models. These IP phones are

endpoints in the overall network topology, which are designed to interoperate with

other compatible equipments including application servers, media servers,

internet-working gateways, voice bridges, and other endpoints. These IP phones are

characterized by a large number of functions, which simplify business communication

with a high standard of security and can work seamlessly with a large number of SIP

PBXs.

SIP-T48G, SIP-T46G, SIP-T42G, SIP-T41P, SIP-T29G, SIP-T27P, SIP-T23P/G, SIP-T21(P) E2 and

SIP-T19(P) E2 IP phones provide a powerful and flexible IP communication solution for

Ethernet TCP/IP networks, delivering excellent voice quality. The high-resolution graphic

display supplies content in multiple languages for system status, call log and directory

access. IP phones also support advanced functionalities, including LDAP, Busy Lamp

Field, Sever Redundancy and Network Conference.

The following IP phone models are described:

 SIP-T48G

 SIP-T46G

 SIP-T42G

 SIP-T41P

 SIP-T29G

 SIP-T27P

 SIP-T23P/G