Why do all cordless handsets ring at once and show Line in Use?
Answer
This usually points to a line or base-station problem rather than one bad handset. Power-cycling the AT&T EL52213 base, checking the phone jack and DSL/filter setup if used, and testing with a corded phone often isolates whether the issue is the cordless system or the phone line itself.
Before you start: stop right away if…
- Unplug the base from power before handling cables, and do not open the base unit.
Follow these steps
Power-cycle the base
Unplug the AT&T EL52213 base from both power and the phone jack. Wait about 2 minutes, then plug the phone line back in first and power second.
You should see: Handsets resync to the base and the Line in Use message clears, or the same fault returns immediately.
Test the wall jack with a corded phone
If available, plug a basic corded phone into the same wall jack and listen for dial tone, crackling, or silence.
You should see: A clear dial tone means the cordless system is more likely at fault; no dial tone or heavy crackling points to the phone line or jack.
Check filters and splitters
If the home has DSL or other shared-line equipment, confirm the cordless base is on a filtered phone port and that filters or splitters are firmly connected.
You should see: Connections are secure, and crackling or false Line in Use behavior improves after correcting filter placement.
Reduce other line devices
Temporarily disconnect other devices on the same phone line, such as fax machines, alarm dialers, or extra cordless bases, then retest with only the EL52213 connected.
You should see: The line stays stable with only the base connected, or the problem continues even with other devices removed.
Contact the phone provider if outages repeat
If the corded-phone test fails or multi-day Line in Use outages keep returning, report a line issue to the phone provider and give the dates and duration of each outage.
You should see: The provider can test the line or schedule a repair if the fault is outside the cordless phones.
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Extra tips
What to look for: The Line in Use message on the handsets, crackling on pickup, and whether a simple corded phone on the same jack works during the outage.
Before you change anything: Note the exact model on the base, such as AT&T EL52213. Have a corded phone ready if available for a line test. If you have DSL internet on the same line, locate any phone-line filters before unplugging cables. Avoid opening the base or cutting phone wires.