The University will put new telephone services on-line later this month when it implements the first part of a Centrex system upgrade.

The services, which include linking the Medical School area to a University-wide system for the first time, are the start of an effort to replace the "obsolete and expensive" network currently in use with the 5ESS Intellipath System, said Anne H. Margulies, assistant director for the Network Services of the Office for Information Technology.

"The new system will put everyone on the same network. It makes things simpler," Margulies said.

As of December 16, administrators, faculty and staff with telephone numbers in the 495 and new 432 Medical Center exchanges will be able to transfer, forward and hold calls. The new system will also allow users to distinguish between calls placed from other University lines and those from outside Harvard.

In addition, Margulies said that the University has added a 496 exchange--formerly used on Cape Cod--because the 495 prefix has reached its capacity.

Individuals at the University previously received many of the Intellipath features at added cost from their telephone companies. For at least the next year, however, the Harvard University Network--which operates Intellipath--will offer the services to administrators and departments at no added cost. But students may have to be content to order them through New England Telephone until as late as 1991.

Monthly telephone charges will also rise as a result of the changes, but just how much for each customer has yet to be determined.

"Cost will go up but not by much. They tell uscost goes up because of what we are requesting,"said Ruby M. Aguirre, department administrator forthe Mathematics Department.

Despite the cost increase, "Any new system willbe better than what we have right now," said RobinT. Ochs, department administrator for theDepartment of Romance Languages and Literatures.

And Aguirre said, "All the telephones getdisconnected here a lot. They told us that theywould not with the new system."

The Harvard University Network will also allowadministrators, departments and later students toorder telephone service through the University,instead of through New England Telephone,Margulies said