A multi-line remotely-accessible Controller which allows the user of a conventional cordless telephone to selectively access any of a number of telephone lines in a private or in-house telephone system, through the use of the Dual-Tone Multi-Frequency (DTMF) signals transmitted by the handset of the...http://www.google.co.uk/patents/US5826196?utm_source=gb-gplus-sharePatent US5826196 - Multi-line remotely-accessible controller for cordless telephones
