Although you can use your 2-line telephone with a single phone line, you must have two lines (separate phone numbers) to use a two-line system. The following diagrams show two possible systems:
Two Lines on a Single Modular Jack
One type of two-line phone system uses a single RJ14 modular jack which contains both phone lines. Connect the phone cord to the LINE 1+2 jack.
You must use a 4-conductor telephone line cord like the gray one packed with your unit.
