Command Communications Comswitch 5500 3-Port Phone/Fax Modem Line Sharing Device

From the Manufacturer

Distinctive Ring mode for simple line sharing - When you add a second phone number to your single line, the CS 5500 works smoothly with Distinctive Ring service offered by most local phone companies (different companies have various names for this service; check with your phone company for details). In short, the CS 5500 is able to recognize specific ring patterns assigned to your different phone numbers and route calls to the right device.
Yes, you can use phone company Voice Mail and Caller ID - We've made it possible for the CS 5500 to work with Voice Messaging from the phone company (requires Distinctive Ring service activation). The system is also compatible with Caller ID service (requires service activation).
Monitoring - ComSwitch 5500 is so smart it stays on the line during every call, listening for tone commands you send from the keypad of a telephone. So you can talk for a few minutes, push three keys, and transfer the call to your fax machine to receive a document. All on the same call.
* Two 8K In-Line Microfilter phone filters are required - available from most consumer electronics stores.