The XHFC-2S4U is a single-chip ISDN transceiver for two resp. four ISDN S/T or UpN/Up0 Basic Rate Interfaces with integrated HDLC controllers for all kinds of BRI equipment. XHFC-2S4U has two Universal ISDN Ports which can be configurated either in S/T mode or in Up mode, numbered 0 and 1. Two additional Up interfaces are available, numbered 2 and 3. The integrated microprocessor bus interface of the XHFC-2S4U can be configured to 8 bit parallel microprocessor interface or serial processor interface (SPI). A PCM128 / PCM64 / PCM30 interface for CODEC or inter-chip connection is also integrated. The deep FIFOs of the XHFC-2S4U are realized with an internal SRAM.

Block Diagram

XHFC-2S4U Block Diagram


  • Line interfaces

  • 4 ISDN interfaces, two are selectable as S/T or UpN/Up0 interfaces (Universal ISDN Ports), two operate always as UpN/Up0 interfaces
  • S/T ISDN interfaces in TE and NT mode conform to ITU-T I.430 and TBR 3
  • Up signal range exceeding UpN/Up0 specification
  • simple external line interface circuitry

  • HDLC-controller and FIFO controller

  • universal HDLC controller for all B-, D- and E-channels, can also be used for PCM time slots
  • transparent mode and data rate independently selectable for all FIFOs
  • up to 16 FIFOs for transmit and receive data each, FIFO size configurable from 64 up to 256 bytes per FIFO, maximum 7 HDLC frames per FIFO
  • B- and D-channels can be combined for higher data rate to 128 kBit/s (2B) or 144 kBit/s (2B+D) per line interface
  • Bit Error Rate Test (BERT) with transmitter and receiver
  • programmable data flow to connect FIFOs, ST / Up interfaces and PCM time slots with each other

  • PCM interface

  • PCM128 / PCM64 / PCM30 interface configurable to MST (MVIP)TM or Siemens IOM-2TM and Motorola GCITM (monitor and C/I-channel support) for interchip connection or external CODECs
  • programmable PCM time slot assigner for 16 channels in transmit and receive direction each (switch matrix for PCM)
  • H.100 data rate supported on PCM bus
  • flexible PCM synchronization options implemented, synchronization input and output signals available

  • Microprocessor bus interface

  • improved 8 bit parallel microprocessor interface compatible to Motorola bus and Siemens / Intel bus, multiplexed and non-multiplexed modes supported
  • high performance serial processor interface (SPI), up to 16 XHFC devices addressable with one /SPISEL signal
  • auto-configure mode for repeater applications without microcontroller (only external EEPROM needed)

  • Miscelleanous features

  • flexible interrupt controller, timer and watchdog with interrupt capability
  • programmable PLL with big range of clock frequencies for general purpose usage (can also be used to generate the internal system clock)
  • 6 GPIO pins can be used instead of every unused line interface, further 8 GPIOs can be enabled separately as second pin function
  • 2 general purpose pulse width modulators (PWM) with dedicated output pins

  • Technology features

  • single 3.3V power supply, CMOS technology 3.3V, 5V tolerant on nearly all inputs
  • PQFP 100 package, 0.65mm pin pitch
  • RoHS compliant


  • VoIP gateways / VoIP routers

  • Integrated Access Devices (IAD)


  • IP Centrex / Hosted PBX

  • ISDN least cost routers

  • ISDN LAN routers

  • ISDN test equipment

  • Call recording

Linux Driver

Generic Linux drivers for XHFC-2S4U are available upon request.

Evaluation board of XHFC-4SU    

Evaluation Board

Contact us for an evaluation board of XHFC-2S4U.


Get Datasheet

Copyright © 2011 Cologne Chip
The ISDN Chip Company!
Last Modified: 03/05/2011