Keithley Instruments Inc. offers a modular test system suitable for automated, high-channel-count applications. The Model 4500-MTS is designed to test fiber optic telecommunications system components such as tunable laser diodes, laser diode modules, Raman amplifier pump laser modules and other active optoelectronic devices. The company says that the system has sufficient power source capability, throughput and accuracy to significantly lower the cost of testing and manufacturing. The expandable test platform is built on an open PCI backplane architecture with nine card slots. It can be used with series 4500 Quad I-V cards to simultaneously characterize the light-current-voltage performance of 36 laser diodes in a multihead test fixture.