One option, many benefits

DISA (optional)
This facility allows external callers to dial directly to the extension they require, after following the guidance message issued by the system.
This helps to ease the load of a busy operator, and connects calls quickly and easily to the callers chosen extension.

Fax detect (optional)
Routes incoming fax messages automatically to extensions with a fax machine.

OGM card (optional)
A simplified 'auto attendant' operation helps handle callers and direct them to key departments: sales, service, accounts etc.