US Patent 10326886 Enabling additional endpoints to connect to audio mixing device

A system capable of connecting a device to a wired communication network (e.g., Public Switched Telephone Network (PSTN)) using an adapter. During a telephone call using the PSTN, the adapter may mix two or more audio streams to enable multiple devices to join the telephone call. However, the adapter has limited resources. If the adapter receives a request from an additional device to join the call, the adapter may send a notification that indicates a maximum number of endpoints has been reached. To enable audio mixing for additional devices, the system may send multiple audio streams to a communication server to be mixed and the mixed audio stream are sent to the adapter to be output using the PSTN. The communication server may receive the audio streams from the adapter or directly from the devices.