The LTB 1024 device is a line test and measurement box specifically designed for A²B® technology, an emerging automotive audio bus.

The device can measure the bus voltage and the bus current between A²B® nodes during the bus operation, simulate fault insertion on both A²B® lines and provide a load simulation.

Bus voltage and current can be monitored independently to A²B® line status and activity. The measurement device is capable of sampling both values up to 12bit resolution.

The fault insertion part can provide shorts to a reference supply (e. g. to a DUT supply to simulate a fault) or a short between both A²B® lines to interrupt the bus operation and to test the bus diagnostic feature.

A third function is the load simulation, which can be implemented by connecting an external user selectable resistive load to the LTB 1024.

All simulation modes are performed with non-mechanical switches to have no influence on the A²B® lines in normal operation and to offer a long service life with no loss of performance.


  • Voltage, current and power measurement between nodes on the A2B® bus
  • Short-circuit fault insertion for testing the A²B®-Transmitters diagnostic functions
  • External load connection for simulating passive A2B® nodes and testing phantom power feature
  • Device can be placed anywhere on the A2B® bus, no extra bus configuration is needed
  • Compatible with AD240x, AD241x and AD242x, AD2433 transceivers
  • Industrial grade connectors for the A2B® bus compatible with NOFFZ ITD 1024 or with other  A2B® bus test devices


  • LTB 1024 Test Panel Application for initial setup into operation and laboratory setup
  • .NET Framework API DLL (32 & 64 bit)
  • NI LabVIEW API (32 & 64 bit, LabVIEW 2012 and higher)
  • NI TestStand API (32 & 64 bit, TestStand 2012 and higher)

See also our other products for A2B testing


A2B® Interface - Input1, in direction to a master
A2B® Interface - Output1, in direction to slaves
PC-CommunicationRS232 interface
Daisy ChainRS485 interface,
up to 16 devices in chain

Voltage RangeUp to 32 V
Current RangeUp to 0.5 A
Resolution1 mA; 1 mV

External Load 
CurrentUp to 400 mA in total

Fault modes 
Fault Insertion Cases
on the A2B® lines
Short of Wires
Positive/negative wire shorted to ground
Positive/negative wire shorted to VBAT

Power Requirements 
Voltage12 VDC
Current0.5 A (max.)
Power SupplyIncluded, 100 – 240 VAC/50 – 60 Hz

Physical Specifications 
Dimensions130 mm x 36.5 mm x 90 mm (W x H x D)
Weight225 g


pdf-download Produktdatenblatt


Some examples of arranging the LTB 1024 with different combinations of master and slave for measuring voltage and current

  • Voltage and current measurement using one LTB in a simple A²B® network containing one master and one slave device
  • A setup to monitor voltage and current between all nodes within an A²B® network containing one master and three slaves
  • A setup to measure voltage and current between two slave nodes