The CT2 counter-timer module is for counting all sources of TTL pulses including all ET Enterprises TTL photon-counting modules and TTL amplifier-discriminators. It has an RS232 computer interface.  View outline drawing.

  • 100 MHz capability
  • 32 bit count capability
  • integral microcontroller and RS232 interface to the host computer
  • trigger input for synchronous counting


The following operating modes are available with the software application provided:

  • continuous readings
  • fixed number of readings
  • continuous readings with trigger high
  • fixed number of readings - start on falling edge of trigger

Software and User Manual

A comprehensive manual giving installation, start up software and programming procedures is supplied on CD-Rom with every CT2 module.

An ActiveX ® control driver is also provided to allow users to develop their own control software using LabView ®, Visual Basic ®, etc.


An RS232 cable is included with every CT2.

Also, a cable LEADAD6CT2 is available to connect an AD6 amplifier discriminator. The CT2 supplies the AD6 power requirements through this cable.



Power Supply

    connector 2.1 mm power socket  
    voltage +4.75 to 5.5 V  
    current 60 mA max at 5 V  

Signal Input

    connector BNC socket  


    edge speed 125mV / ns min, 0.8 to 2.0 V  
    minimum pulse width 5.0 ns  
    pulse pair resolution 8.3 ns  
    maximum frequency* 100 MHz  
    sample time 10 ms to 300 s  

RS232 interface

    connector 9 pin 'D' socket  
    baud rate 9600  
    format no parity, 8 data bits, 1 stop bit  

User interface

    connector Hirose 6 pin chassis plug  
    trigger input TTL  
    out 1 TTL; sink 20 mA, source 80 µA  
    out 2 open drain FET**  


    weight 175 g  

*with ultra fast photomultiplier, and using dead time correction
**sink 60 mA, on resistance 0.45 Ω max.

Download CT2 software

Download CT2 data sheet

Download CT2 manual

© ET Enterprises Limited 2011-2015
ET Enterprises is a trading name of ET Enterprises Limited. Registered in England & Wales, company number 06081468.