Hi
The optiXstar C810 and C820 are CPE devices.
The CPE is a customer premises equipment (CPE). It is usually installed in the customer equipment room of the private line and connects to the aggregation device in the central office (CO) equipment room of the carrier.
This devices is used when the distance between the client equipment and the transmission equipment is very far.
Take the OptiXstar A810 A as an example. The OptiXstar A810 A provides a maximum line-side rate of 2.5 Gbit/s and supports E1 and FE/GE multi-service access. It provides a cost-effective solution for small-granularity high-quality private line scenarios. It is mainly used for private line access of government and enterprise branches. This type of equipment can be used when the ISP's communications equipment room is far away from the communications equipment room of an enterprise. This saves a lot of money.

Thank you!