Evaluation Board

The HFC-4S/8S Evaluation Board PCI card allows to use up to four/eight line interfaces and is made of the following functional parts:

  • the HFC-4S/8S microchip
  • four RJ45 connectors
  • pin headers for the remaining four interfaces (HFC-8S only)
  • a socket for a power feeding module (optional)
  • a PCI bus connector
  • a PCM interface connector
  • 100Ω termination switches for each interface
  • TE/NT mode jumper switches
  • four user-configurable status LEDs (HFC-4S only)


Driver software plays an important role in all ISDN projects. This consideration leads to one of the basic principles of Cologne Chip: individual support for each project.
By having broad knowledge about ISDN applications, the support team of Cologne Chip will assist in finding the best approach regarding system architecture and concerning software aspects.

Linux drivers are available for all chips as open source software. Under the terms of GPL (GNU Public Licence) the source code of the Linux drivers may be used free of royalities.
Wheter a project is done as an in-house development or in cooperation with a design house as 3rd-party, Cologne Chip is committed to in-depth technical support for fast time-to-market.

Go to the official repository.

Transformer Selection Guide

Customers of Cologne Chip can choose from a variety of transformers. The relevant requirements for selecting the right transformer for each ISDN Interface are as follows:

Basic Rate (S/T)

compatible to XHFC and HFC series

  1. Turns ratio of 1:2 (line side : chip side)
  2. Center tap on chip side (required for Cologne Chip receiver circuitry)

Several companies provide transformers and transformer modules that can be used with our ISDN Basic Rate and Primary Rate Interface controllers. Most popular are SMD modules with chokes for EMI reasons.