SIM Toolkit: Network & Signal

Most signal apps dump numbers on you. SIM Toolkit tells you what they mean, what's wrong, and takes you straight to the fix.

HEALTH CHECK — PLAIN-LANGUAGE ANSWERS
• "You're roaming in South Africa and data roaming is off, so mobile data won't work" — with a button to the right setting
• Weak signal vs. interference: know whether to move closer to a window or just a few metres
• Network rejections explained: "Roaming not allowed in this area (cause 13)" and what to do
• Dual SIM tip: "SIM 2 has much better signal here — switch your data SIM"

SIGNAL — EVERY NUMBER, GRADED AND EXPLAINED
• Live signal score (0–100) plus RSRP, RSRQ, SINR, RSSI, CQI for 5G NR, 4G LTE, 3G and 2G — tap any metric to learn what it means
• 5G NSA / 5G SA / LTE-Advanced (4G+) detection and carrier aggregation widths
• Serving cell: band, downlink/uplink frequency, EARFCN/NR-ARFCN, PCI, TAC, cell ID with eNB/sector
• Distance to the tower from timing advance
• Nearby cells and a live signal graph
• Compare both SIMs side by side

SIM — WHAT YOUR SIM AND PHONE ARE ALLOWED TO DO
• Carrier, MVNO brand, home network, phone number (when stored on the SIM), eSIM or physical SIM
• Is your phone carrier-locked? (Android 14+)
• Carrier features on this phone: VoLTE, Wi-Fi Calling, VoNR, backup calling, 5G NSA/SA, hotspot
• Emergency numbers for the country you're in — ideal for travel
• Honest about what Android hides: we show where to find your ICCID and IMEI instead of blank fields

TOOLS — DO SOMETHING ABOUT IT
• Open your carrier's SIM Toolkit (STK) menu for each SIM
• Network mode shortcut to Android's hidden Phone info menu (e.g. LTE only / NR only, where your phone allows it)
• One tap to data SIM, roaming, APN, Wi-Fi calling, network operator and SIM PIN settings
• USSD console: balance and bundle codes with the carrier's reply shown in the app, plus call forwarding, call waiting and caller ID codes
• Find the best spot: a full-screen meter with a tone that speeds up as your signal improves
• Status-bar signal meter (live dBm and 4G/5G) and a Quick Settings tile
• Signal log with handovers, drops, time on 5G/4G/3G, and CSV or KML (Google Earth) export
• Band & frequency calculator
• Share a network report with your carrier's support in one tap

PRIVATE BY DESIGN
• No internet permission: the app cannot send your data anywhere
• No ads, no analytics, no account, no tracking
• Location is only used because Android requires it to read cell towers, and it never leaves your phone

Signal values come straight from your phone's modem; some manufacturers report fewer details than others. Hidden menus and shortcuts depend on what your phone's manufacturer allows.