# Secret Codes guides and tips URL: https://shahid09.is-a.dev/blog/secret-codes/ App: Secret Codes: IMEI & Carrier (https://apps.apple.com/us/app/secret-codes-imei-carrier/id6807154322) Author: Muhammad Shahid Khan 317 verified iPhone dial codes for IMEI, call forwarding, caller ID, voicemail, eSIM and carrier services, plus a full device diagnostic suite. Nothing is locked. **Quick answer:** Secret Codes: IMEI & Carrier is a free iPhone & iPad app by Muhammad Shahid Khan (Dial codes, SIM & network test). This page lists all 10 guides for it. Each one answers a single real question in plain language, with screenshots from the app. ## All Secret Codes guides - [iPhone Secret Codes That Actually Work in 2026 (and the Ones That Don’t)](https://shahid09.is-a.dev/blog/iphone-secret-codes-that-work/): The iPhone codes that work are mostly standard GSM codes and carrier codes, dialled in the Phone app: *#06# shows your IMEI, *3001#12345#* opens Field Test mode, *#21# checks call forwarding, *#43# checks call waiting and #31# before a number hides your caller ID on many networks. iPhones have no hidden engineering menus, so Android codes like *#*#4636#*#* do nothing. - [How to Check Your IMEI on iPhone (5 Ways, Even Without the Phone)](https://shahid09.is-a.dev/blog/how-to-check-imei-on-iphone/): The fastest way is to dial *#06# in the Phone app. You can also go to Settings > General > About and scroll to IMEI. Without the phone, check the original box or sign in to your Apple Account on the web and look at your device list. On some models it is also on the SIM tray. - [Call Forwarding Codes for iPhone: *#21#, ##002# and the Full GSM List](https://shahid09.is-a.dev/blog/call-forwarding-codes-iphone/): On GSM networks: **21*number# forwards all calls, *#21# checks if forwarding is on, and ##21# turns it off. Use 67 for busy, 61 for no answer and 62 for unreachable. ##002# cancels all forwarding at once. On iPhone you can also use Settings > Phone > Call Forwarding, where your carrier supports it. - [How to Hide Your Caller ID on iPhone (#31#, *67 and Settings)](https://shahid09.is-a.dev/blog/hide-caller-id-iphone/): To hide your number for one call, dial #31# before the number on many GSM networks, or *67 before the number in the US. To hide it for all calls, turn off Show My Caller ID in Settings > Phone, where your carrier offers it. Dial *#31# to check your current setting. Your number is still shown to emergency services. - [How to Check if Your iPhone Is Unlocked (Carrier Lock Explained)](https://shahid09.is-a.dev/blog/check-if-iphone-is-unlocked/): Go to Settings > General > About and look at Carrier Lock. If it says "No SIM restrictions", your iPhone is unlocked and works with any compatible carrier. Anything else means it is locked to a carrier, and only that carrier can unlock it. Unlocking is done by the carrier on its systems, not with a code. - [What Does ##002# Do on iPhone? Cancel All Call Forwarding (and Keep Your Voicemail)](https://shahid09.is-a.dev/blog/what-does-002-do-on-iphone/): ##002# is a standard GSM code that erases every call forwarding rule on your line at once: unconditional (21), busy (67), no answer (61) and unreachable (62). On iPhone, dial it in the Phone app and press Call; your network replies with a short confirmation. It is safe, but on many networks voicemail works through conditional forwarding, so missed calls may stop going to voicemail until it is set up again. - [*#21#, ##21# and **21*: What These Call Forwarding Codes Mean on iPhone](https://shahid09.is-a.dev/blog/what-does-star-hash-21-mean/): They are GSM codes for unconditional call forwarding (service code 21): *#21# checks whether all your calls are being forwarded, ##21# erases that forwarding, #21# pauses it, and **21*number# forwards every call to that number. Only dial **21* with a number you chose yourself, because scammers use it to steal calls. - [*#31#, #31# and *31# on iPhone: What They Do and How to Turn Them Off](https://shahid09.is-a.dev/blog/what-is-31-code-iphone/): Service code 31 controls outgoing caller ID on GSM networks. #31# before a number hides your number for that call. *31# before a number shows it for that call when it is hidden by default. *#31# on its own checks whether your number is hidden on your line. If your calls always show as No Caller ID, turn on Show My Caller ID in Settings or ask your carrier. - [iPhone Field Test Mode (*3001#12345#*): How to Check Your Real Signal Strength](https://shahid09.is-a.dev/blog/iphone-field-test-mode/): Dial *3001#12345#* in the Phone app and press Call to open Field Test mode. For 4G, open the menu and choose LTE > Serving Cell Meas: rsrp0 is your signal strength in dBm. Closer to zero is better: above -80 dBm is excellent, -80 to -100 is good to fair, and below -110 dBm is weak. Signal bars are only a rough summary of these numbers. - [Android Secret Codes on iPhone: *#*#4636#*#*, *#0*# and What to Use Instead](https://shahid09.is-a.dev/blog/android-secret-codes-on-iphone/): Android codes such as *#*#4636#*#* and *#0*# open menus built into Android or Samsung software. iOS has no hidden engineering menus, so they do nothing on an iPhone. The iPhone equivalents are in Settings (battery health, model, Wi-Fi address), in Field Test mode (*3001#12345#*) for signal, and in diagnostic apps or Apple Support for hardware tests. ## Common questions about Secret Codes ### Do secret codes work on iPhone? Some do. Standard GSM codes like *#06#, call forwarding and call waiting codes, carrier codes and Apple’s Field Test code work. Android engineering menu codes do not. https://shahid09.is-a.dev/blog/iphone-secret-codes-that-work/ ### How do I check my IMEI on iPhone? Dial *#06# in the Phone app, or go to Settings > General > About and scroll down to IMEI. https://shahid09.is-a.dev/blog/how-to-check-imei-on-iphone/ ### How do I check if my calls are forwarded? Dial *#21# for unconditional forwarding, and *#67#, *#61# and *#62# for busy, no answer and unreachable forwarding. https://shahid09.is-a.dev/blog/call-forwarding-codes-iphone/ ### How do I hide my number on iPhone for one call? Dial #31# before the number on many GSM networks, or *67 before the number in the US. https://shahid09.is-a.dev/blog/hide-caller-id-iphone/ ### How do I check if my iPhone is unlocked? Go to Settings > General > About and look at Carrier Lock. "No SIM restrictions" means it is unlocked. https://shahid09.is-a.dev/blog/check-if-iphone-is-unlocked/ ### What does ##002# do? It erases every call forwarding rule on your line at once: all calls, when busy, when not answered and when unreachable. It is a standard GSM code handled by your network. https://shahid09.is-a.dev/blog/what-does-002-do-on-iphone/ ### What does *#21# do on iPhone? It checks whether unconditional call forwarding is on. It only shows the status and changes nothing. https://shahid09.is-a.dev/blog/what-does-star-hash-21-mean/ ### What is #31# used for? Dialled before a number on GSM networks, #31# hides your caller ID for that call. The other person sees No Caller ID or Private. https://shahid09.is-a.dev/blog/what-is-31-code-iphone/ ### What is *3001#12345#*? Apple’s code for Field Test mode, a hidden screen that shows detailed cellular measurements, including real signal strength in dBm. https://shahid09.is-a.dev/blog/iphone-field-test-mode/ ### Does *#*#4636#*#* work on iPhone? No. It opens a testing menu built into Android. iOS has no hidden engineering menus, so nothing happens. https://shahid09.is-a.dev/blog/android-secret-codes-on-iphone/