Grandstream currently has a line of Analog Telephone Adapters (ATA)[1] that fit this use case. [1]: https://www.grandstream.com/products/gateways-and-atas/anal

Grandstream currently has a line of Analog Telephone Adapters (ATA)[1] that fit this use case. [1]: https://www.grandstream.com/products/gateways-and-atas/analog-telephone-adaptors https://www.grandstream.com/products/gateways-and-atas/analo...