The two sides have been in talks for months and are understood to be close to reaching terms at below Hawthorn's current market price of 2.5p, valuing it at about pounds 4m. The shares hit a peak of 73.5p in 1989.
The company has been struggling with debts of more than pounds 25m, most of which are owed to Svenska Handelsbanken of Sweden, but Vodaphone is expected to clear these.
Last month Hawthorn announced that it was in discussions with a mystery suitor that may lead to an offer.
Hawthorn, which provides a mobile telephone service to about 40,000 subscribers, ran into severe financial problems because of a hectic acquisition strategy masterminded by Remo Dipre, who owns 70 per cent of the group.
Mr Dipre was forced by the company's bankers to step down as chairman in July 1991. Last autumn the company reported a turnaround from a pounds 9m loss to a pounds 434,000 taxable profit for the half year to 30 June.Reuse content