Basic modules

LCPU. Linux IP Attachment

LCPU. Linux IP Attachment

With the Linux Central Processor Unit (LCPU) it is possible to realize public address announcements from remote locations as well as the networking of systems over the Internet.

At a Glance:

  • DVS-21 system networking over a LAN
  • Public address over video workstation
  • VoIP connection (according to H323 standard / SIP)
  • Digital announcement machine (up to approx. 4000 min.)
  • Audio and signal transmitting
  • Secure data transmitting
  • Standardized interfaces
  • Function expansion through various attachments

The following block diagram illustrates the functionality of the LCPU:

Block diagram LCPU
Block diagram LCPU

The LCPU has a modular structure and consists in the core of

  1. The circuit board with the serial and the LAN interface
  2. The Linux attachment (mandatory)
  3. The BusCPU (soldered on)
  4. The audio attachment (slide-in)
  5. The compact flash card (CF card)

About a):

The circuit board has a multilayer design. The various attachments, (b – e) are slid in from the top.

The following interfaces are accessible at the front:

  • 10/100 Mbit LAN (RJ45)
  • USB V1.1 type A (master)
  • USB V1.1 type B (slave)

About b):

The Linux attachment regulates bus communications. It supports all features of the Linux kernel 2.6.

Main computer data:

XScale PXA 250 with 400 MHz
64 MByte SDRAM (32 bit @ 100 MHz)
32 MByte flash memory (32 bit), expandable to
up to 2 GByte over CF card

About c):

The BusCPU is responsible for properly scheduled bus switching for the DVS-21. Data exchange from and to DVS-21 goes over the PCM bus. A UART interface works as link between the LCPU and BusCPU.

About d):

The audio attachment manages the scheduled control of low frequency (LF) data received over a LAN over Linux computers to BusCPU and vice versa.

About e):

A compact flash card (up to 2 Gbyte) to save data can be used.

The LCPU can be fitted with an additional attachment. Currently there are three standard attachments available:

  • E1 attachment, L- No. 2.860
  • S0 attachment, L- No. 2.870
  • UART attachment, L- No. 2.880

The LCPU set 4 is assigned the mode of operation, E1, S0 or UART in the configuration software ICS depending on the attachment it is equipped with. The BusCPU on attachment manages communications between the LCPU and DVS-21.


  • Screen (management) workplace
    • Public address for remote locations over up to 64 DVS-21 systems as live public address or through stored text files
    • Public address of multiple video workstations to the same destinations
    • Assigning of up to 20 priorities per system - Configuration also as disruption notification PC
  • DVS-21 system networking over a LAN (LCPU to LCPU)
  • Digital announcement machine (voice storage function)
  • VoIP applications for DVS- 21
  • Automatic announcement device / passenger information system (DeutscheBahnAG)

Details can be found in the application descriptions.

The Front Plate Symbols and their Meaning:

The System Blinker The System Blinker
Addressing fro processor taking place
I/O Input/Output
BUS output works as push-push operation with the system blinker
BUS input works as push-pull operation with the system blinker
The System Blinker Receiving
Attachment receiving signal (depending on set)
The System Blinker Sending
Attachment receiving signal (depending on set)
On Status Display
Attachment ready for operation
Al Alarm

Technical Data:

Operating Voltage: +/-5 V (control)
Operating Current (+5V): 200 mA
Operating Current (-5V): 4 mA
Temperature Range: 0 °C to 45 °C
Weight: 300 g
Installation Height: 3HE
Installation Width: 6TE