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Single Line Telephone

After an IP-based or traditional TDM telephone service has been established, a physical telephone must be chosen. While most users will use a single line telephone, multi-line sets are also available.

A traditional TDM single line phone set is a basic phone, similar to telephones that most users might find in their own homes, made up of a handset and base with a keypad. Though the TDM basic single line phones are simple, they can allow for additional features as required to suit the user's needs.

IP-based single line telephone sets offer many advanced services and features, including mobility and presence. More information IP-based single line sets is available at User Guides.

Features of single line phones are accessed through keypad commands beginning with either the star or pound keys. You must "flash" the switch hook to activate features for calls in progress. The switch hook is the button on the set which detects that the handset has been returned to its cradle when you hang up.

To "flash" the switch hook while a call is in progress, fully depress the switch hook for one second, and release it. You will hear a stutter dial tone followed by a standard dial tone confirmation that the switch hook has "flashed."


The following features are programmed on your TDM and IP-based telephone by default:

For more information on how to use these features and to see what other features are available, please see User Guides.


To install a single line phone, the building must have Northwestern IT telephone service available and an existing jack. If the desired jack has another service active in it, such as data service, it will need to be deactivated before the new service can be activated.


To order phone service including a new phone number, a University work order contact must submit the request using the CONDUITS Online Order Form. All orders must include:

To order a new handset for an existing phone number, please follow the instructions above, but also provide:

Last Updated: 24 March 2017

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