Internal PBX Systems for Companies | Falcon Security Systems

Sizing a PBX properly the first time

The two numbers that define a PBX are external lines and internal extensions, and companies routinely get the first one wrong. Extensions are easy to count — one per desk. External lines are about how many simultaneous outside calls you need, which is almost always far fewer than the number of staff.

A reasonable starting ratio for a normal office is one external line per six to eight extensions. A telesales operation needs far more; a workshop where the phone rings occasionally needs far fewer. Paying for external lines you never use simultaneously is the most common waste in a PBX project.

Buy the extension capacity you will need in two or three years, not today. Extension cards are cheaper as part of the original system than as an upgrade, and a system at its capacity limit forces an awkward decision the moment you hire.

Do not underestimate the cabling. A PBX project in an occupied office is mostly a cabling project — the exchange itself installs in an afternoon. Running extension cable to twenty desks through a finished office is what determines the timeline and most of the cost.

Before ordering, confirm

• Peak simultaneous external calls, not total staff
• Extension count you expect in two to three years
• Whether desks already have usable cabling
• Whether you need call recording or reporting
• Who will administer extensions when staff change