General
Product type	a/b switching module
Compatibility	TFS-Dialog 200/300/400, TFS-Universal a/b, TFS-Universal plus
Maximum number of modules per installation	6
Control	Via a/b line
Key assignment	Selectable
Mounting location	Underfloor mounting box

The Auerswald a/b-switch module, type 90638, is an add-on module for intercom systems of the TFS-Dialog series (200/300/400) as well as for the TFS-Universal a/b and TFS-Universal plus models. It serves to extend the functionality of door intercom stations by enabling additional switching functions. When a doorbell button is pressed, this module can, for example, turn on lighting, activate an existing doorbell, or inform an intrusion alarm system of a visitor's presence. The modules are directly integrated into the existing a/b line, eliminating the need for additional cabling.

Applications
This switch module is specifically designed for use in existing intercom system configurations where an extension of switching functions is desired. It is suitable for residential and commercial buildings where intelligent control of auxiliary functions such as lighting, doorbells, or alarm systems via the door intercom station is required. Installation is carried out without additional wiring, as the module connects to the existing two-wire a/b line. The modules fit easily into standard in-wall boxes, enabling discreet installation.

Functions and Equipment in Detail
The module enables control of up to six a/b-switch modules connected to a TFS-Dialog 200/300/400, TFS-Universal a/b, or TFS-Universal plus. Each doorbell button can control one or more switch modules, with the assignment being selectable. This allows for flexible configuration, where, for example, one button triggers multiple functions while another activates only a single function. The switching functions are transmitted via the a/b line, keeping cabling simple and cost-efficient.

Technology Explained Simply
The a/b-switch module operates via the existing a/b line, which runs between the door intercom station and the telephone system. When a doorbell button is pressed, an electrical impulse is sent through the line, activating the switch module. The module then switches on the connected load, such as a lamp or doorbell. The modules are designed to be directly clipped into the line without requiring additional connections or adapters. Communication takes place via the a/b line, which is intended for signal transmission between the door intercom station and the system.

Compatibility and Accessories
The module is compatible with TFS-Dialog models 200, 300, and 400, as well as with TFS-Universal a/b and TFS-Universal plus intercom systems. It can be used in combination with other a/b-switch modules, with up to six modules per system being possible. Suitable accessories include the TFE / TFS-Dialog 303 and the TFS Dialog 304, which can also be integrated into the existing intercom infrastructure.

Installation and Mounting
Mounting is done by direct integration into the existing a/b line. The modules are compact in size (W x H x D: 45/35/10 mm) and can be easily installed in existing in-wall boxes. No additional tools or special mounting procedures are required. Installation can be carried out without interrupting the existing system, as the module is simply clipped into the line.

Operational Advantages
By integrating the a/b-switch module into existing intercom systems, functionality is extended without the need to lay additional wiring. The flexible assignment of switching functions to individual buttons enables customized use. The modules are compact and can be mounted discreetly, preserving the aesthetics of the installation. Utilizing the existing a/b line reduces installation costs and simplifies maintenance.