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Telephone Number Assignment

The assignment of telephone numbers at the NIH are managed electronically through the centralized 5ESS Switch based on their availability.  While telephone number assignment is automatic, CIT Telecommunications can offer customers unique telephone number set-ups to enhance their ability to communicate effectively with the public and the NIH community

Other specialty services available to our NIH customer are:

Vanity Numbers are unique telephone numbers that can be dialed using a meaningful alphanumeric  representation appropriate to identify the user or service, e.g. 301-594-6248 (GO-CIT), 301-594-4357  (HELP), 1-800-NIH-HELP, etc. 

Easy Numbers are telephone numbers that becomes universal for a region or designated customer base and are delineated by the ease in dialing and remembering the number, e.g. 301-594-4444 or 1-800-444-8000

Toll Free Numbers are reserved and maintained at the discretion of the long distance provider and are exempt from this process.  The CIT Telecommunications Specialist will refer the customer to the designated person responsible for managing and implementing FTS Networx long distance services.

National Institutes of Health Telephone Number Exchanges

To reach the National Institutes of Health, callers from OUTSIDE and INSIDE the NIH community require a 10-digit number, which includes Area Code plus a 7-digit number.   Once familiar with the first three digits of the 7-digits, the NIH community can recognize callers as INSIDE (ON the 5ESS Switch) or OUTSIDE (OFF the 5ESS Switch).  The following exchanges are recognized as INSIDE:

                                                             214 (Exclusively for Emergency Phones)
                                                            *827 (Used by NIH & FDA)

Note:  The 827 NNX is used by both NIH and FDA, so these numbers may be both Inside and Outside of the NIH Community.

National Institutes of Health Emergency Back-up Telephone System

The 214 Exchange is exclusive to NIH Red Emergency Phones to be used when the other exchanges are not operational.  To find dialing instructions and view a full list of EMERGENCY BACK-UP NUMBERS and associated organizations go here.

Telephone Line Suspension/Disconnection

An NIH Institute may, at any time request that a telephone number be suspended or disconnected as part of a Telephone Service Request or a Large project that may be in progress.  CIT Telecommunications may also at any time contact an Institute to verify if a telephone number is in use.  At the end of 90 days, and after a thorough review of all existing line information, the CIT Telecommunications Specialist will issue an order to completely disconnect the telephone number(s).  Disconnected telephone numbers are held in de-aging for a period of thirty (30) days and then added to the available pool of numbers for reassignment. For more information on suspending and disconnecting an NIH Telephone, please contact the NIH IT Service Desk @ 301-496-4357 or

For information on ordering other CIT Telecom Services please click here.




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This page last reviewed: November 09, 2011