General
Device type	Extension module
Form factor	Plug-in module
Connection system	Wired
Number of connections	1
Connections	1 x ISDN (switchable between S0 and UP0)
Compatible slots	1 expansion connector
Number of digital connections	1

The Auerswald COMpact ISDN module (type 90581) is an expansion module for the COMpact 3000 series, extending the telephone system with an ISDN connection. It can be used either as an external exchange port (PP) or as an internal port (PMP), enabling the integration of ISDN connections into existing system configurations. The module is compatible with the variants COMpact 3000 analog, COMpact 3000 ISDN, and COMpact 3000 VoIP, and serves as a plug-in module to expand connection options.

Applications
This module is used in companies and facilities requiring an ISDN connection via the COMpact 3000 series. It enables connection to the public telephone network (exchange connection) or linking to internal ISDN end devices. The switchable operation as S0 (4-wire) or UP0 (2-wire) increases flexibility in cabling and connection selection, particularly in existing infrastructures where different cable types are present.

Functions and Equipment in Detail
The module features a single ISDN connection that can be switched between S0 and UP0 operating modes. This switchability allows adaptation to the specific cabling situation. As an external port (PP), it connects to the public telephone network; as an internal port (PMP), it connects to internal ISDN end devices. When used as PP (system connection), note that the trunk number on the module must differ from the trunk number on the main system to avoid network conflicts.

Technology Explained Simply
The module functions as a digital interface module supporting ISDN protocols. The S0 interface (4-wire) is the standard connection for ISDN in Germany, enabling voice and data transmission over a pair of lines with an additional pair for control. The UP0 interface (2-wire) is a simplified variant using only one line pair and can be used in specific environments, e.g., with existing telephone lines. The module is designed as a plug-in module, inserted into an expansion socket of the COMpact 3000 series.

The number of digital connections is one, meaning the module provides a single ISDN port. The connection type is wired, and the module is designed for a single connection.

Compatibility and Accessories
The module is specifically developed for the COMpact 3000 series and can be installed into the expansion slots of these systems. It is compatible with the models COMpact 3000 analog, COMpact 3000 ISDN, and COMpact 3000 VoIP. It is used as an expansion module to extend the system’s functionality with ISDN connection options. No additional accessories or components are mentioned in relation to this module.

Installation and Mounting
Installation is performed by inserting the module into a free expansion socket of the COMpact 3000 system. It is a plug-in module requiring no additional tools or special mounting procedures. Configuration is done via the system control, where switching between S0 and UP0, as well as selecting between external and internal port, is managed through the system software.

Operational Advantages
The module offers flexible expansion options for existing COMpact 3000 systems without requiring a complete new installation. The switchable use as S0 or UP0 increases adaptability to existing cabling. Integration into the system requires no additional hardware, and configuration is possible via the system control. Use as an internal port enables connection to ISDN end devices within the company network.