Secret Codes guide
*#300# on iPhone: Check Calling Name Presentation
By Muhammad Shahid · · 4 min read
Quick answer
*#300#: Ask whether the network sends you the caller's name, not just the number. Service code 300 is CNAP, Calling Name Presentation, specified in 3GPP TS 22. 096 and listed in TS 22. 030 Annex B. It is the supplementary service that delivers the name of a caller name alongside their number, which is what the industry calls caller ID name or CNAM.
Secret CodesDial codes, SIM & network test · Free on the App StoreDownload free →| Code | *#300# |
|---|---|
| What it does | Ask whether the network sends you the caller's name, not just the number. |
| Published for | AT&T and T-Mobile |
| Type | Support varies |
Ask whether the network sends you the caller's name, not just the number. This page explains what *#300# does, how to use it on an iPhone and which carriers it applies to.
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What does *#300# do?
Service code 300 is CNAP, Calling Name Presentation, specified in 3GPP TS 22.096 and listed in TS 22.030 Annex B. It is the supplementary service that delivers the name of a caller name alongside their number, which is what the industry calls caller ID name or CNAM.
The interrogation is read only. Where it answers, it reports whether CNAP is provisioned and active for your subscription.
In the United States caller name is usually resolved by a database lookup rather than by the GSM CNAP supplementary service, and on iPhone the name you see often comes from your own contacts or from a carrier operated caller ID product. That is why this string frequently errors even on lines that clearly do display names.
How do I use *#300#?
- Open the Phone app and tap Keypad.
- Type *#300# 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 in the spec but seldom exposed by US networks, which handle caller name through database lookup instead. An error tells you nothing about whether caller name works on your line. |
Related call barring and sim pin codes
- **03*330*0000*1234*1234#: Change the Call Barring Password
- *43*11#: Turn On Call Waiting for Voice Only
- *#353#: Check All Incoming Barring
- #43*11#: Turn Off Call Waiting for Voice Only
- #353*0000#: Cancel All Incoming Barring
- **04*0000*1234*1234#: Change Your SIM PIN
See all call barring and sim pin codes or every category of 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.
Frequently asked questions
What does *#300# do on iPhone?
Ask whether the network sends you the caller's name, not just the number. Service code 300 is CNAP, Calling Name Presentation, specified in 3GPP TS 22. 096 and listed in TS 22. 030 Annex B.
What else should I know about *#300#?
t is the supplementary service that delivers the name of a caller name alongside their number, which is what the industry calls caller ID name or CNAM. The interrogation is read only. Where it answers, it reports whether CNAP is provisioned and active for your subscription.
What are the steps for *#300#?
1. Open the Phone app and tap Keypad. 2. Type *#300# exactly as written. 3. Press the green Call button and wait for the result.
Where do I use *#300#?
On the keypad of the Phone app.
Do I need to press Call after typing *#300#?
Yes. Type it on the Phone keypad, then press the green Call button.
Is *#300# 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 *#300# work on?
It is published for AT&T and T-Mobile. Defined in the spec but seldom exposed by US networks, which handle caller name through database lookup instead. An error tells you nothing about whether caller name works on your line.
Does *#300# 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 *#300# 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 *#300# 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 *#300#?
**03*330*0000*1234*1234#: Change the Call Barring Password. Register a new network password for the call barring services.
What else is in this category?
*43*11#: Turn On Call Waiting for Voice Only. Enable call waiting for telephony while leaving other services alone.
Sources
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