You may be trying to troubleshoot a problem with your iPhone, or just looking for certain information for your own knowledge, and you’re having trouble finding the right features or settings.

Instead of hunting through the usual screens, you can reveal and even change certain details and settings via the right dialer codes. By typing a specific sequence of numbers and characters at the keypad, you can access key features that would otherwise be difficult to find.

Here’s a list of dialer codes and the information they’ll retrieve for you.

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Ways to use iPhone dialer codes

Check the IMEI Number

Similar to a serial number, the IMEI number is used to identify your phone type, carrier, network, country and other details. A mobile carrier will sometimes ask for the IMEI number to assist with troubleshooting or account changes.

You can find the IMEI number by searching through your Settings screen, but using a dialer code is easier. At the keypad, tap *#06#, and the number appears along with the EID and MEID numbers (Figure A).

Figure A

Image: Lance Whitney/TechRepublic.

Check your data usage

These codes differ by carrier. For AT&T, tap *3282#. For Verizon Wireless, tap #3282. And for T-Mobile, tap #932#.

After tapping the code, press the call icon to place a call to your carrier. The resulting information appears as a text message or notification showing how much data you’ve used for the current billing cycle. Don’t forget to hang up the call after the text has arrived (Figure B).

Figure B

Image: Lance Whitney/TechRepublic.

Enter field test mode

Field test mode displays a lot of technical data about cellular activity, most of which is likely useless to you but may be of help to an engineer or support person trying to assist with a technical problem. To access this mode, tap *3001#12345#* and then tap the call icon. The resulting dashboard reveals information about your bandwidth and related metrics (Figure C).

Figure C

Image: Lance Whitney/TechRepublic.

Make a test call

To make sure your phone’s calling feature is working, you can place a test call, though this seems only to be available with Verizon. To try this out, dial #832. An automated message should tell you that your test call was successful (Figure D).

Figure D

Image: Lance Whitney/TechRepublic.

Turn off caller ID for your phone

If you’re testing your phone’s ability to make calls and don’t want your number to show up on the other end, you can turn off caller ID when dialing a specific number. To do this, type *67 followed by the number, as in *67-555-123-4567. Your number will show up as private or anonymous on the receiving phone (Figure E).

Figure E

Image: Lance Whitney/TechRepublic.

Check your account balance

You can find out how much you owe on your current bill through a dialer code, which varies slightly by carrier. For AT&T, enter *225# at the keypad. For Verizon Wireless, enter #225. And for T-Mobile, enter #225#. Tap the call icon. A text or notification then appears with your account balance (Figure F).

Figure F

Image: Lance Whitney/TechRepublic.

View your minutes and messages

Finally, you can see how many minutes you’ve used for your calling plan in the current billing cycle. For AT&T, dial *646#. For Verizon, dial #646. For T-Mobile, dial #646#. Tap the call icon. A text message or notification displays the number of minutes and messages you’ve used for the current cycle (Figure G).

Figure G

Image: Lance Whitney/TechRepublic.