Adds 3 lines and 8 telephone capacity for Partner ACS phone systems and higher - Caller ID built-in (Caller ID must be provided by local carrier) - Fax detection and routing available Universal Port Structure allows multi-line analog phones or single-line devices (fax machine, credit card machine, modems, etc.) Additional Details ------------------------------ Product description: Adds 3 lines and 8 telephone capacity for Partner ACS phone systems and higher - Caller ID built-in (Caller ID must be provided by local carrier) - Fax detection and routing available Universal Port Structure allows multi-line analog phones or single-line devices (fax machine, credit card machine, modems, etc.)