Credit: Amir Bohlooli / MUO

There are plenty of hidden Android features, but one category that predates Android — and smartphones entirely — is shortcodes. Your phone’s dialer isn’t just for calling numbers or your carrier; certain strings you type there can run internal programs on the device. These are called shortcodes.

There are shortcodes for all sorts of functions. Most were designed as diagnostic tools for engineers and repair technicians, which is why you’ll rarely see them mentioned in user guides or marketing. Among them, there’s one stands out, as a sort of master code, because of how much information it reveals about your device.

The secret code that opens Android’s debug menu

Better call *#*#4636#*#*

That’s the code. Open your Phone app, type *#*#4636#*#*, and you’ll see a new screen appear automatically after the final asterisk. You don’t need to press call. This screen opens a hidden testing menu with at least three submenus. I say at least because Android isn’t a unified experience — manufacturers modify it heavily — so what you see may vary.

On my Nothing Phone (1), I get three options: Phone information, Usage statistics, and Wi-Fi information. The first is the most revealing, so let’s start there.

Phone information

SIM meets science

The Phone information page focuses less on the flashy hardware of your smartphone and more on its original purpose: connecting to cellular networks. It’s packed with technical data about your SIM, IMEI, and how your device communicates with nearby towers.

At the top, you’ll see your IMEI, the unique hardware ID embedded into your phone. Below that, there’s your phone number and IMSI, which ties your SIM card to your carrier. These aren’t groundbreaking —you can find them in Settings — but keep scrolling. The good stuff comes next. Next is the Network section. Current network shows which carrier you’re on, **Roaming **confirms whether you’re outside your home network, and Data service tells you if mobile data is active. So far, nothing new.

If you use multiple SIMs, there’s a Select phone index option that lets you switch between them.

Then comes Data network type — this one matters. The icon on your status bar might say “4G” or “5G,” but that’s shorthand. This page shows the exact technology your phone is using. It’s like game console generations: both the Xbox One and PS4 were “eighth-gen,” but they were completely different systems. Likewise, several underlying network technologies can all be considered “3G” or “4G.” Here, you see the truth behind the icon.

Real signal metrics

Below that are your signal metrics. This is the real measurement of your signal strength that’s far superior to the bars on top of your screen. I’ve written before about using these values to find the signal sweet spot in my home. Here, you’ll see the same data, but in richer detail. The table below shows what the values mean:

Signal strength value (dBm)	Signal quality
-80 to -90	🟦Excellent
-91 to -100	🟩Good
-101 to -105	🟨Fair
-106 to -110	🟧Poor
-111 to -120	🟥Weak
-121 and below	⬛No signal

ASU is Android’s internal (and somewhat arbitrary) scale. It’s less standardized, but moves in the same direction. For both of these, the greater the value the better (I’m embarrassed I have to clarify this, but just in case: yes, -80 is greater than -100). Further down, there’s All mobile measurement info. This lists every tower your phone can detect.

Term	Meaning
SRV	Serving or neighbor tower
EARFCN	E-UTRA Absolute Radio Frequency Channel Number; LTE frequency channel, which helps identify the band (like Band 3 or 7)
RSRP / RSRQ	Power and quality readings for each tower

Another toggle worth noting here is Mobile radio power. Turning this off disables your cellular modem entirely — similar to Airplane Mode (why does it still exist?), but without killing Wi‑Fi or Bluetooth. Calls, texts, and mobile data will stop, but the rest of your connectivity stays up.

Preferred network type

The second tweakable option here is Preferred network type. You can also set this in Android’s main Settings, but there it’s limited to generations (5G/4G/3G). This menu, however, lets you pick technologies directly. I was personally curious to know what each of these mean, and since I’ve already written two tables, here’s another:

Term	Stands for	Generation	Meaning / Role
GSM	Global System for Mobile Communications	2G	First global digital standard for calls and texts.
CDMA	Code Division Multiple Access	2G/3G	Rival 2G tech used mainly in the US.
WCDMA	Wideband CDMA	3G	3G evolution for GSM
UMTS	Universal Mobile Telecommunications System	3G	GSM upgrade using WCDMA for data.
HSPA / HSPA+	High Speed Packet Access / Plus	3G	Faster 3G variant, up to 42 Mbps.
LTE	Long Term Evolution	4G	IP‑based network with lower latency.
LTE‑A	LTE‑Advanced	4G	Combines frequencies for higher throughput.
NR	New Radio	5G	5G radio interface supporting sub‑6 GHz and mmWave.
NSA / SA	Non‑Standalone / Standalone	5G	NSA uses a 4G core; SA is full 5G.

This level of control is useful if you prioritize stability over raw speed. A solid LTE signal often beats a flaky LTE‑A one. If you identify a stronger nearby tower, you can force LTE‑only for better reliability.

Change Mobile info refresh rate from **Disable **to **Instant **to see live updates.

There’s much more buried here — radio states, PDP contexts, IMS registration — but those are beyond this writing. Let’s move to the next section.

Wi‑Fi information and usage stats

The rabbit hole of acronyms

Select Wi‑Fi information, then Wi‑Fi config. You’ll be met with an even denser screen: rows of SSIDs, MAC addresses, and authentication details. This is your phone’s Wi‑Fi configuration dump. If your device is new and hasn’t connected to many networks, it’ll be shorter. Mine was a scroll marathon.

This page looks intimidating but serves a practical role. It lists every saved network, along with its encryption type (WPA2, WPA3, etc.), TLS certificates, and key management protocols. While most users will never need this data, it can help diagnose issues like mismatched security types or bad DHCP leases. I won’t write much about this page because it’s less fascinating conceptually — every modern device connects to Wi-Fi and we’ve seen these metrics on other devices before.

The next menu, Usage statistics, is self‑explanatory and the least exciting. It’s less hidden in modern Android, since you can already find it under **Settings **> Digital Wellbeing. Still, it’s worth opening once — if only to reckon with how many hours you’ve sunk into doomscrolling.

The engineer’s Easter egg

The *#*#4636#*#* menu isn’t new. It dates back to early Android builds and kept alive because it’s too useful to remove. If you’re tech-savvy, you’ve *probably *used it before, but chances are, you hadn’t. And hey, I did say *probably *in the title.

Depending on your phone, it might include even more entries. My colleague’s Nothing Phone 3, for instance, also shows Battery information with stats on charge cycles and temperature.

This code won’t speed up your device or patch your signal, but it exposes the inner workings of the radio stack. Knowing your system is the first step to mastering it.