Effective Feb. 9, the Applied Physics Laboratory will have new telephone area codes and new three-number exchanges.

To reach APL from Baltimore, callers will now have to use a 443 area code and a 778 exchange. For example, the current 410-792-5000 will become 443-778-5000.

Washington callers must use a 240 area code coupled with a 228 exchange. The current 301-953-5000, for example, will therefore become 240-228-5000.

In order to facilitate the change, a grace period during which both new and old numbers will function has been established through March 31. However, all callers are urged to use the new numbers beginning Feb. 9.

Anyone within APL who is aware of callers unable to reach their parties using the new numbers should contact Farida Ali-Overholt at ext. 5750 or Hermie Graham at ext. 5035.