The HFC-4S is a HDLC B- and D-channel controller with 4 integrated S/T interfaces. It can be used for ISDN basic rate lines. All channels are served fully duplex by deep FIFOs. Also implemented is a PCM128 / PCM64 / PCM30 highway interface (which is able to connect to many telecom serial busses) and an universal external bus interface.

Block Diagram

HFC-4S Block Diagram


  • single chip ISDN-S/T-controller with B- and D-channel HDLC support

  • 4 integrated S/T interfaces

  • full I.430 ITU S/T ISDN support in TE and NT mode

  • 32 independent read and write HDLC-channels
    for e.g. 8 ISDN B-channels, 4 ISDN D-channels and 20 timeslots on the PCM interface

  • B-channel transparent mode independently selectable

  • up to 64 FIFOs; FIFO-size configurable

  • each FIFO can be assigned to an arbitrary channel of any S/T or PCM interface

  • max. 31 HDLC frames (with external 128k or 512k SRAM) or 15 HDLC frames (with 32k built-in RAM) per FIFO

  • 1 - 8 bit processing for subchannels selectable

  • 56 KBit/s restricted mode for U.S. ISDN lines selectable

  • B-channels for higher data rate combinable

  • PCM128 / PCM64 / PCM30 interface configurable to interface MITEL STTM bus (MVIPTM) or Siemens IOM2TM and Motorola GCITM (bearer slots supported only) for inter-chip connection (e.g. external CODECs)

  • H.100 data rate supported

  • universal external bus interface configurable into PCI bus, ISA-PnP, PCMCIA or microprocessor interface as well as SPI (serial processor interface)

  • multiparty audio conferences switchable

  • DTMF detection on all B-channels

  • Timer with interrupt capability

  • CMOS technology 3.3V (5V tolerant inputs)

  • MQFP 208 package, RoHS compliant


  • ISDN multi-BRI terminal adapters


  • ISDN LAN routers

  • ISDN least cost routers

  • ISDN test equipment

Linux Driver

Generic Linux drivers for HFC-4S are available.

Evaluation board of HFC-4S    

Evaluation Board

Contact us for an evaluation board of HFC-4S.


Get Datasheet

Copyright © 2007 Cologne Chip
The ISDN Chip Company!
Last Modified: 23/05/2007