This cable enables you to connect our Comet and Meteor Caller ID products to international phone sockets (RJ11 Connection), as well as for use with Analogue Telephone Adaptors for VoIP lines. 
 
If you intend to use your Comet or Meteor product outside the UK, or you intend to use it alongside an Analogue Telephone Adaptor (ATA) with a VoIP line, then  you will need to purchase this cable. The Comet USB and Comet Serial caller ID units are now also available with this cable instead of the UK telephone cable as an option.