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

PX24 Family: Design Principles


A Completely Integrated Hybrid IP PBX Design

Shall a computer, which has numerous hardware and software parts from various vendors used to support TDM ports and IP endpoints, be a total and final solution for small to medium size enterprises? Perhaps not for all. 

Shall an IP-enabled PBX, which is based on a traditional circuit-switched PBX design with additional media gateway boards used to support IP endpoints, be a total and final solution for small to large size enterprises? Perhaps not for all.

Enterprises may like to migrate to IP PBX systems with keeping benefits of the traditional TDM interfaces. They may also expect their new IP endpoints not to be complicated. They may prefer these looking like their traditional TDM users.

Consequently, we have designed our PX24 Hybrid IP PBX Business Phone Systems as very integrated systems. They are capable of interworking between all its IP and TDM users. Each variant of incoming and outgoing calls associated with a TDM signaling or IP protocol generates and receives telephony events within the core operating software Xymphony of the PX24. A complete, fully integrated, and a single software avoids the conflicts of distributed software packs and control units. In addition, the telephony task co-ordination is handled reliably. Many TDM user services are also valid for IP endpoints. Consequently, enterprises are in comfort of both VoIP and traditional services.

Minimalist Approach in IP PBX Design, But 


`Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.`

Antoine de Saint-Exupery

French writer (1900 - 1944)

Architects, graphic designers, authors, many other artists and designers have employed this minimalist approach to succeed. An architect may aim to design a house with the smallest size and investment but with all the comfort inside. Is it easy? Definitely not. Sure! the perfection is not easy to achieve.

Being a very specific, is such a minimalist approach the right way to succeed in designing an IP PBX? Yes, but be aware that:

  • Product quality means more for VoIP services. This being the case, the product should be minimalist in terms of investment and size but it should be Robust, Reliable and Stable too.
  • The product should fit the expectations of enterprises now and in the future. In minimalism, keeping hardware and firmware capabilities limited will definitely cause dissatisfaction in time.
  • Efficiency of the operational firmware is very important. An efficient firmware will definitely need less memory space, less MIPS, less hardware. The result will be less investment and size.

If designers believe in their experience (especially for the firmware development) that a Robust, Reliable, and Stable IP PBX with flexible hardware and firmware features can be designed in small size with small investment then the minimalist approach is the right way to start. 

We have done it. Consequently, PX24 Hybrid IP PBX Business Phone Systems employ a control and switching unit with a size of only 8x10cm.

A Unique Example to the Minimalist Approach in IP PBX Design : PX24N (Telesis Nano)

Telesis PX24N is the latest in our product line and reflects our minimalist approach in design. 4 analog DC loop trunks (FXO ports), 8 analog subscribers (FXS ports), and 32 IP (SIP, or H.323, or xSIP) users (local or remote, subscriber or trunk) are located in a unique box, featuring an executive digital phone too.

The PX24N image

The photo above is not only an executive telephone set but much more inside!...


The PX24N bottom view

A nano hybrid IP PBX and executive digital telephone in the same box.

Combining Advantages of Both Proprietary and Open-source Systems in IP PBX Design

Open-source IP PBX suppliers claim that costs of their systems are less than similar proprietary IP PBXs. They also say that an open-source IP PBX has manufacturer independent peripherals, and customers are not restricted to only using peripherals and software provided by the manufacturer.

On the other hand, proprietary system suppliers claim that their systems are more robust, stable, and field-proven. Technical support behind their systems is powerful. They also say that their systems keep the benefits of the traditional interfaces and services.

In fact, both sides may have further claims. We respect all of these claims. Both sides are correct in their perspectives. Both open-source and proprietary systems may have advantages. When designing the PX24 Hybrid IP PBX Business Phone Systems, we have studied and analyzed all these advantages.

So, many technological and commercial factors have influenced the design and optimization of the PX24 systems, and our marketing strategy. Consequently, we have added many features and services in PX24 systems without any extra cost.

Furthermore, we continuously add new features into the operating systems of PX24 systems. We distribute new firmware releases free of charge. We provide freeware utilities like XTools and XCom. We also provide the details of some communication protocols for software developers. Consequently, software enthusiasts and developers may develop their own:

  • API clients (like PC consoles)
  • CMDR reporting utilities
  • PMS (property management system) Front Desk utilities
  • Archiving and reporting utilities for automatic conversation records 
  • External call processing servers for:
    • automatic voice response to customers, which are listed in a database
    • pre-paid telephony
    • black lists (blocking customers, which are listed in a database)
    • forwarding customers, which are listed in a database, to right representatives or service groups

The PX24 Hybrid IP PBX Business Phone Systems are equipped with various TDM interfaces. The analog subscribers are driven by the standard 48Volt. So, any standard analog telephone with or without Caller ID, may be connected. Caller ID encoders and decoders are also standard in PX24 systems. The manufacturer independent terminal equipment types for PX24 systems are:

  • Standard analog phones
  • Standard analog phones with Caller ID
  • Euro ISDN phones
  • SIP hard and softphones (wired or wi-fi)
  • H.323 hard and softphones (wired or wi-fi)
  • DECT phones
  • Any Java enabled web browser in any operating system to make web calls


PX24 Hybrid IP PBX Business Phone Systems are:

  • Integrated systems
  • Robust, reliable, and stable systems
  • Without hardware and software limitations
  • Small-size systems
  • Proprietary systems but also with the advantages of open-source systems

Copyright Telesis A.S. 2006-2013
STB Design Services