NASHVILLE, Tenn. (AP) _ Northern Telecom and Bell Atlantic Corp. said Monday they have formed a partnership to market private telecommunications systems in the mid-Atlantic region.

Northern Telecom, a maker of digital communications switching systems, will have a majority interest and managing role in the partnership. Bell Atlantic is a regional phone company serving middle Atlantic states.

No other terms were disclosed.

The partnership will be known as Bell Atlantic Meridian Systems. As part of the deal, it acquired the assets of Bell Atlanticom Systems Inc., a wholly owned subsidiary of Bell Atlantic.

The subsidiary will sell and service Northern Telecom's Meridian 1 private branch exchange and Meridian Norstar key systems, used mostly by businesses with multiple telephone lines. More than 800 Bell Atlanticom employees will join Meridian Systems.

John T. Losier, formerly a vice president of marketing for Northern Telecom, will be president of Bell Atlantic Meridian Systems.

Joseph M. O'Hara Jr., formerly president and chief executive officer of Bell Atlanticom, will be vice president of operations.

Bell Atlantic Meridian Systems will be headquartered in Princeton, N.J., with sales offices in Morristown, N.J., Philadelphia, Pittsburgh, Baltimore, Richmond, Va., and Washington, D.C.

The partnership is similar to ones Northern Telecom already has with two other regional phone companies, Nynex and Pacific Telesis.

Bell Atlantic Corp. is the parent company of New Jersey Bell, Bell of Pennsylvania, Diamond State Telephone (Delaware), and the Chesapeake and Potomac Telephone Companies of Maryland, Virginia, West Virginia and Washington.