Thomas Cook UK & Ireland has outsourced the management of its phone system to save £20m over five years.
The travel company has hired T-Systems to manage the system in partnership with its existing service provider, Energis, which will provide the voice circuits.
Servicing will be handled by Redbridge and all hardware supplied by Alcatel. The contract covers 615 high street stores, the firm's Peterborough head office, three data centres and other offices.
T-Systems will consolidate disparate voice systems and equipment, reduce complexity in the system, and deliver new phone features to employees.
Thomas Cook is considering extending the managed service contract to its businesses in France, Belgium, the Netherlands and Germany.