It is recommended to upgrade this Avaya Product soon.
This analog phone uses a line for voice, giving you one voice channel. Fax and some alarm companies also use analog lines.
The Partner MLS-12 Telephone is made for users who frequently multi-task. It features a full-duplex speakerphone, enabling hands-free usage so that users can type and perform other tasks while talking.Partner MLS-12 (Avaya) User Guide