OLT (Optical Line Terminal) is the endpoint hardware device located at the central office in a Passive Optical Network (PON). The OLT contains a central processing unit, a gateway router, voice gateway uplink cards and passive optical network cards. The main functionality of the OLT is to adapt the incoming traffic (voice/data/video) from the metropolitan rings into the PON transport layer. It can transmit a data signal to users at 1490nm wavelength. That signal can serve up to 128 ONTs at a range of up to 12.5 miles by using Optical Splitters. Fiber-Mart provides OLTs for both EPON and GPON systems.