The socket on the router is for a conventional phone, and quality depends entirely on the CODEC used by vodaphone for their 'Voip like' service. Для крепления к стеблям в пробке выполняется пара отверстий под проволочное соединение. A Voip phone would connect to one of the Ethernet sockets, most likely https://55opt.org/catalog/iskusstvennye-kolokolchiki/