Cleveland--Advanstar Communications announced Wednesday that is has agreed to acquire Essen, Germany-based Gruppe 21 Informations-GmbH. The deal gives Advanstar the Documents, Messaging and Security (DMS) trade show and Info 21 magazine, both of which serve the electronic information management industry. Neil Jones, Advanstar's European managing director, said the deal will allow the company to strengthen its other products in Germany. ``We already have plans to locate our computer telephony event, Voice Germany, for example, alongside DMS to take advantage of the synergies that exist to the benefit of both customer bases,'' Mr. Jones said. DMS and Info 21 will join Advanstar's global information technology group.