Electronic – Details about Total Access Communication System (TACS)

This question cannot be answered without a lot more information regarding the multi-line phones.

Many later model business telephone lines use different interface protocols between the phones and control unit back in the telephone equipment room than the typical "tip and ring" connections used by a "cheap two line phone".

The business phones may be using digital signalling or a combination of digital and analog signalling. The the "cheap" phone will be using the analog type of signalling.

The theoretical coverage area of a given cellular (or other UHF) transmitter will be circular, if it uses an omni-directional antenna - but most of the cell sites I've seen have multiple directional antennas, so the actual coverage area may have a non-circular shape. Buildings and other obstructions may also alter the shape of the coverage area.

When making a conceptual drawing of multiple cell cites, it is common to show each cell's coverage as a hexagon, as that results in the most compact "packing" of cell sites. In practice, cell sites can't be placed in a perfect hexagonal pattern, but that pattern works well for general discussions of the cell system.