Telesis PX24 IP PBX Business Phone System
Design and manufacture IP PBX Business Phone System, Switching System, VoIP Gateway, and Signaling Converter  

xSIP - eXtended SIP

Telesis Systems Offering eXtended SIP

  • Telesis Business Phone Systems:
    • PX24N (Telesis Nano) IP PBX SoHo System
    • PX24M Hybrid IP PBX Business Phone System
    • PX24X Hybrid IP PBX Business Phone System
  • Telesis Switching Systems:
    • X1 Large Capacity TDM - IP Telephony Switch
  • Combined VoIP Gateway and Signaling Converters:
    • Stillink 200
    • Stillink 800
    • Stillink 3200
  • Large Capacity IP PBX for Enterprises
    • Stillink 3200

Telesis Phones with eXtended SIP

  • Telesis VTS480 Executive IP Video Telephone
  • Telesis XPhone VoIP Softphone for PC


xSIP (eXtended SIP) protocol has been developed by Telesis. The main purpose of its development is to make some value-added services in Telesis systems to be applicable for VoIP calls too. Presently, Telesis offers several products with xSIP protocol. All xSIP products bring the comfort of Telesis digital sets over IP. Almost all the functions of Telesis digital telephones are also applicable over IP. To illustrate, VTS480 and XPhone are with a busy display panel showing the current status (idle, busy, ringing, etc.) of 120 pre-programmed users in a Telesis Hybrid IP PBX.

General Services with the xSIP

Telesis systems support numerous xSIP users. Number/IP translation is performed through an advanced routing algorithm. Together with the integrated xSIP registrar, call authorization, call management, enhanced billing functions, flexible routing algorithms, and extensive business telephony features make a Telesis system serve as a feature-rich communication platform.

Extended Services with the xSIP

Some of the extended services with the xSIP protocol and xSIP capable phones are: 

  • accessing to missed calls list, dialed numbers list, incoming calls list, and directory stored in the registered Telesis system,
  • large LCD display with lots of information about the user and registered Telesis system 
  • playing, deleting voice messages and recorded conversations stored in the registered Telesis system, 
  • selecting the ringer melody available in the registered Telesis system,
  • many programmable function keys.
  • many programmable quick access keys and busy display panel (BDP), 
  • setting call forward unconditional,
  • setting call forward busy,
  • setting call forward no-reply,
  • setting hotline,
  • activating call waiting,
  • activating do not disturb,
  • activating wake-up (reminder) service,
  • observing firmware version of the registered Telesis system,
  • deflecting calls,
  • activating call back,
  • holding calls on,
  • retrieving calls,
  • transferring calls,
  • tracing transferred calls (up to 4 calls),  
  • activating conference,
  • recording the conversation bi-directionally (both calling and called party voices).


Telesis VTS480 IP videophone image

VTS480 using xSIP protocol for voice and video calls


ITS821 IP Phone and XPhone IP Softphone (PC edition) for Telesis Hybrid IP PBX Business Phone Systems


XPhone IP Softphone (PC edition) provide extended services over IP

XPhone IP Softphone (Mobile edition) for Telesis Hybrid IP PBX Business systems

XPhone IP Softphone (Mobile edition) for Pocket PC Phone and Smartphone

Layers and Options

The physical layer of xSIP protocol in Telesis systems is 10/100 BaseT Ethernet.

Call Routing

A Telesis system routes a call from the TDM network to the xSIP user according to:

  • Dialed digits (called number)
  • DPC
  • Calling party number and information elements whenever available, such that:
    • Category of calling party
    • NOA of calling party
    • Numbering plan of calling party
    • Presentation status of calling party
    • Screening status of calling party

xSIP and AES 256 Media Encryption

Beyond the comfort and availability of value-added services, xSIP also allows secure communication with utilizing AES-256 media encryption for voice. Telesis Business Phone Systems, TDM-IP Telephony Switches, as well as VTS480 Executive IP Video Telephone Sets (or XPhone VoIP softphones PC edition) support AES-256 over xSIP protocol.

AES 256 is also suppored over xSIP

Telesis xSIP IP telephones connected to a Telesis system. AES 256 media encryption over xSIP

AES 256 is also supported over xSIP

XPhone softphones connected to a Telesis system. AES 256 media encryption over xSIP

Security of VoIP communication between a VTS480 IP Telephone (or XPhone VoIP softphone PC edition) and a Telesis IP Telephony System is ensured with:

  • Proprietary protocol: xSIP
  • Proprietary VoIP codes
  • Intelligent algorithms for authentication
  • Exchange of Diffie-Hellman half keys
  • Cipher AES-256

Related Readings

We recommend you to visit Telesis Wiki Pages for technical readings.



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