POWERS OF ATTORNEY


     KNOW  ALL MEN BY  THESE  PRESENTS,  that the  undersigned  constitutes  and
appoints James L. North,  Howard A.  Thrailkill and John R. Cooper,  and each of
them,  his true and  lawful  attorneys-in-fact  and  agents,  with full power of
substitution,  for  him  and in his  name,  place  and  stead,  in any  and  all
capacities,  to sign the Registration Statement on Form S-8 under the provisions
of the Securities  Act of 1933, as amended,  for the  registration  of 2,000,000
shares of Common Stock of ADTRAN,  Inc.  (the  "Company")  which may be acquired
pursuant to options  available for grant in the future by the ADTRAN,  Inc. 1996
Employees  Incentive  Stock  Option  Plan  and to sign  any  and all  amendments
(including  post-effective  amendments)  thereto,  and to file the same with all
exhibits  thereto  and  other  documents  in  connection  therewith,   with  the
Securities and Exchange  Commission,  granting unto said  attorneys-in-fact  and
agents,  and each of them,  full power and  authority to do and perform each and
every act and thing  requisite or necessary to be done,  as fully to all intents
and purposes as he might or could do in person,  hereby ratifying and confirming
all that  said  attorneys-in-fact  and  agents  or any of them,  or their or his
substitute or substitutes, may lawfully do or cause to be done by virtue hereof.
         This 18th. day of June, 1997.



/s/ Mark C. Smith
Mark C. Smith


/s/ Howard A. Thrailkill
Howard A. Thrailkill


/s/ Lonnie S. McMillian
Lonnie S. McMillian


/s/ O. Gene Gabbard
O. Gene Gabbard


/s/ William L. Marks
William L. Marks


/r/ Roy J. Nichols
Roy J. Nichols



/s/ James L. North
James L. North