The Retell 157 connector is device that will connect a telephone into a PC to record your calls. The Retell 157 is just a connection so you will need to have the call recording software on your PC already.
To connect the Retell 157 connector you simply plug it into the telephones handset socket, and then plug the other end of the Retell 157 connector into the 3.5mm sound card microphone socket.
The Retell 157 is compatible with the majority of analogue and some system phones, however if the sound quality is low you may need the Retell 650 Intelligent Call Recording Interface.
Retell 957 Software Compatible
If you do not have any call recording software on your computer then the Retell 157 connecter will work with the Retell 957 software. In fact the Retell 957 Lite, and Retell 957 Pro comes with the Retell 157 connector already.