Engenius make exceptional long range cordless phones. The Durafon range incorporate a larger handset but have features more suited to multiple handsets.
The FreeStyl 1 long range telephone offers users a slim and lightweight handset design, with ranges of up to 6 floors of building penetration, 25,000 square feet and 10 acres. 
- 6 floors in-building penetration
- 25,000 sq. ft. of facility coverage
- 10 acres of property, open land coverage
- Single Line (1-ports / line per base unit)
- Multiple handsets (up to 9 per base unit)
- Works behind any analog port (PBX, VOIP, PSTN, FXS or POTS)
- Supports portable handset models FreeStyl1HC only
- Speakerphone (handset & base unit)
- Wireless full duplex intercom between FreeStyl base & other FreeStyl handsets
- PTT (push to talk) Broadcast PA between FreeStyl base & FreeStyl handsets
- Slim & lightweight handsets designed for residential and office environment
- Easy to install and easy to use
- 4.5 hours talk time, 70 hours stand-by time