Frequently asked questions (FAQs)

Welcome to the AT&T product support center. To get started: select a product category from the left, or enter your model number below to go straight to support and troubleshooting for that product.

Product Troubleshooting

Problem:

Why does it show LINE IN USE on my handset or base display?

Solution:

Tip 1 of 4

L1 (or L2)> IN USE is displayed on the base when a system handset is active. It is also displayed on the handset(s) when the base speakerphone is active.

An active extension phone sharing the line will also cause this message to be displayed.

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Note:


You may want to reference your product manual.