Replacing the phone line on a gate call box or entry phone
Telephone entry systems at gates, apartment lobbies and office doors work by calling the resident's or tenant's phone. The visitor talks to them, and the resident presses a key to open the door. On older systems that call goes out over a copper phone line, and when the line is retired, visitors are stuck at the gate.
Updated October 16, 2026 · Twisted VoIP
What the makers say
DoorKing, one of the largest makers of gate and entry systems, puts it plainly: "A POTS Connection is no longer recommended or supported by DKS." It recommends switching to cellular or VoIP, and sells a cellular control box for its systems that runs on AT&T's LTE network.
Source: DoorKing cellular control box.
Your options
| Maker's cellular kit | VoIP line | Line replacement | |
|---|---|---|---|
| How it works | A cellular box built for your brand of entry system | The system connects to a VoIP adapter on your network | A box gives the entry system a working phone line over cellular |
| Remote programming | Usually supported for that brand | Depends on the system | Voice works; dial-up modem programming may not |
| Good fit | One entry system of a brand that offers a kit | Sites with reliable internet at the gate | Sites replacing other copper lines too: alarms, elevator phones, fax |
Ooma AirDial, which we sell, is a line replacement. Ooma lists building entry and gate systems among the systems it supports.
Source: Ooma AirDial.
What to test before you cancel the copper line
- Calling a resident from the directory, both a cell phone and a landline if your residents have both.
- Opening the gate or door with the key press from the resident's phone. This depends on the tones getting through cleanly.
- Calls to a resident who doesn't answer, so the system hangs up properly.
- Remote programming, if your manager updates the directory from an office computer. Older systems program over a dial-up modem, which may not work on every replacement.
- Battery backup, so visitors can still call if the power is out.
Steps to switch
- Find the make and model of the entry system and the phone number it uses.
- Check cellular signal at the call box. Gates are often at the edge of the property, where signal can be weak; an outside antenna helps.
- Pick an option: the maker's kit, VoIP, or a line replacement such as Ooma AirDial.
- Run the tests above with your gate or access company.
- Cancel the copper line once everything passes.
Is your line on a filing?
Questions
Will residents need to change anything?
Usually not. The entry system still calls the same resident numbers. Only the line the system calls out on changes.
Can one replacement box cover several gates?
An AirDial box has four phone ports, so it can serve several lines in one spot. Gates far apart usually each need their own box or their own connection.
Our entry system is old. Do we have to replace it?
Not always. A line replacement can keep an older system calling out. If the maker no longer supports it, or remote programming matters to you, replacing the entry system may be the better spend.
Get a plan for your lines
Tell us what runs on your copper lines. We'll check the filings for your address and tell you what we'd replace each line with. No obligation. Prefer to talk? Call 623-307-5548.
Related guides
General information, not legal or code advice. Requirements depend on your state, your local authority and your equipment.