# *#33# on iPhone: Check Call Barring URL: https://byshahid.com/blog/check-call-barring-star-hash-33-iphone/ App: Secret Codes: IMEI & Carrier (https://apps.apple.com/us/app/secret-codes-imei-carrier/id6807154322) Author: Muhammad Shahid Updated: 2026-11-04 > *#33#: See whether outgoing calls are restricted on your line. Call barring is a network-level restriction on which calls a line may place or receive. This string interrogates the outgoing-call barring setting. US carriers rarely provision barring for consumer lines, so an error response here is the normal result. - **Code:** *#33# - **What it does:** See whether outgoing calls are restricted on your line. - **Published for:** AT&T and T-Mobile - **Type:** Support varies See whether outgoing calls are restricted on your line. This page explains what `*#33#` does, how to use it on an iPhone and which carriers it applies to. I build **Secret Codes: IMEI & Carrier**, a free iPhone app with 317 checked codes and guides, including this one. If you would rather tap than memorise, [get Secret Codes on the App Store](https://apps.apple.com/us/app/secret-codes-imei-carrier/id6807154322). ## What does *#33# do? Call barring is a network-level restriction on which calls a line may place or receive. This string interrogates the outgoing-call barring setting. US carriers rarely provision barring for consumer lines, so an error response here is the normal result. ## How do I use *#33#? - Open the Phone app and tap Keypad. - Type *#33# exactly as written. - Press the green Call button and wait for the result. ## Which carriers does this apply to? | Published for | AT&T and T-Mobile | | Type | Support varies | | Good to know | Defined by GSM but seldom provisioned on US consumer plans. Expect an error on most lines. | _Screenshot: The Secret Codes detail screen shows the steps, the carriers and an Open in Phone button._ ## Related network and signal - [#43#: Turn Off Call Waiting](/blog/turn-off-call-waiting-hash-43-iphone/) - [Choose Your Network Manually](/blog/choose-your-network-manually-iphone/) - [*43#: Turn On Call Waiting](/blog/turn-on-call-waiting-star-43-iphone/) - [Switch Between 5G and LTE](/blog/switch-between-5g-and-lte-iphone/) - [*#43#: Check Call Waiting](/blog/check-call-waiting-star-hash-43-iphone/) - [Wi-Fi Calling](/blog/wi-fi-calling-iphone/) See all [network and signal](/blog/iphone-codes/network/) or [every category of iPhone codes](/blog/iphone-codes/). ## How Secret Codes helps Secret Codes keeps this and every other entry a search away. Pick your carrier once and each entry says whether it is published for your line. You can save favourites, add a private note, and record whether a code worked on your line. This entry is part of Secret Codes Pro. **Secret Codes: IMEI & Carrier** is free on the App Store: https://apps.apple.com/us/app/secret-codes-imei-carrier/id6807154322 ## FAQ ### What does *#33# do on iPhone? See whether outgoing calls are restricted on your line. Call barring is a network-level restriction on which calls a line may place or receive. This string interrogates the outgoing-call barring setting. ### What else should I know about *#33#? US carriers rarely provision barring for consumer lines, so an error response here is the normal result. ### What are the steps for *#33#? 1. Open the Phone app and tap Keypad. 2. Type *#33# exactly as written. 3. Press the green Call button and wait for the result. ### Where do I use *#33#? On the keypad of the Phone app. ### Do I need to press Call after typing *#33#? Yes. Type it on the Phone keypad, then press the green Call button. ### Is *#33# a hidden or secret code? No. It is a published service, not a hidden menu. iPhones do not have Android-style engineering menus. ### Which carriers does *#33# work on? It is published for AT&T and T-Mobile. Defined by GSM but seldom provisioned on US consumer plans. Expect an error on most lines. ### Does *#33# work on Android phones too? It is handled by the carrier or service rather than the iPhone, so it is not tied to one phone brand. Check with your carrier. ### Will *#33# work outside the US? It is published for US carriers and services, so do not count on it abroad. Ask your carrier before you travel. ### What if *#33# does not work on my iPhone? Check that it applies to your carrier first, because carriers decide which services they offer and can change them. If it should apply to your line, contact your carrier. ### What is related to *#33#? #43#: Turn Off Call Waiting. Send second calls straight to voicemail instead. ### What else is in this category? Choose Your Network Manually. Force your iPhone onto a specific network. ## Sources - [3GPP TS 22.030: Man-Machine Interface of the phone](https://www.3gpp.org/dynareport/22030.htm) - [Apple Support: iPhone User Guide](https://support.apple.com/guide/iphone/welcome/ios)