PMX Phone System

PMX connection via IP

Number portability and assignment

• If you change provider, you can take your existing phone number with you
• When you order a new PMX connection, you will receive a new phone number from the provider’s phone number pool.
• Usual number blocks: 0-499 or 500-999

• If you have several PMX connections, you can even be assigned a complete block from 0-999
• If you only need one connection but would like a larger number block, a block from 0-99 is recommended
• Additional extensions can be added via your telephone system (PBX) itself

Advantages of ISDN

• ISDN offers many functions that other technologies often do not have
• Examples: Franking machines, door opener systems

PABX system with PMX ISDN interface

• If you use a PABX system with a PMX ISDN interface, you can still choose between several providers depending on your location

Advice and availability

• You can use independent expert advice to find the right provider.
• Alternatively: Check availability at your location directly with an online check.

Features of a PMX IP

ISDN offers a standardized structure, but additional functions that are mainly only possible via ISDN:

• Call forwarding directly in the exchange
• Charge display during and after the call
• Call number display or suppression
• Fax transmission
• Signals for franking machines and door systems

In addition, many providers offer:

• Flat rate or per-minute models
• Online tools for simple and transparent billing

PMX IP Provider

The market for PMX-IP provider connections has grown considerably.

In addition to established providers such as Deutsche Telekom, Colt, Plusnet and Vodafone, numerous new providers have joined the market.

These offer innovative solutions with modern user guidance and integration options – e.g. via SIP trunks or cloud telephone systems.

It’s worth comparing providers – not only because of the costs, but also in terms of the service:

• Service Level Agreements (SLAs)
• Additional options
• Bundle offer (e.g. IP telephony or VoIP)

Costs of a PMX connection

The exact costs of a PMX connection depend on the technical conditions. With most carriers, you can book individual additional services – so you only pay for what you actually need.

Some providers offer different PMX variants that differ in their scope of services.

Deutsche Telekom, for example, divides its PMX offering into different packages.

In principle, it is economically worthwhile if you use at least four S0 connections or eight voice channels.

The search for the right provider can be time-consuming and complex.

Our experts compare all available providers and create a clear recommendation with the best price-performance ratio.