The variable attenuator is ideal for simulating cable loss for lab testing of link power margin or reducing power in links where receivers are being overloaded. The variable attenuator is of the gap-loss type. Pulling the connector end-faces apart induces the loss. Since the light exists in an expanding cone, the receiving fiber will capture less light, as the gap gets larger. An air gap attenuator is ideal for use with any LED systems and many laser systems. Some laser systems, especially high-speed digital links (over 1 GB/s) or analog CATV systems may not operate well with the attenuator due to back reflections; you should use the ATT120 with a FC/APC connector, if you use an attenuator in those types of systems. The variable attenuator fits to cables with the connector type shown in the specification. If you need to use the attenuator with other connector types, use hybrid cables. The fiber type used should also match the network fiber type, with one exception: if in a single mode network receivers are used with a multimode “bucket” fiber, you can use a matching multimode fiber on the receiver side of the attenuator.