How to open Field Test Mode
Open the Phone app, enter *3001#12345#* and press the call button. A Field Test dashboard should appear when the carrier and device support it.
Menu names can change between iOS releases. Look for serving-cell, LTE, NR, 5G or radio-measurement sections. If a metric is absent, the current modem or network may not expose it.
The measurements worth recording
Take a screenshot or write down the network type, timestamp and location with the values. The same number means little if the measurement type is unknown.
- RSRP: received reference-signal power for LTE or 5G.
- RSRQ: radio quality affected by interference and load.
- SINR: desired signal compared with interference and noise.
- Cell or physical-cell identifiers: technical context that may change as the phone moves.
Turn one reading into a useful comparison
Measure from the same phone in several controlled locations. Compare near a window, in the problem room and outdoors, then run a speed test in each place.
A stronger RSRP with poor SINR may still produce unstable data. A radio reading should be interpreted with quality, network type and real throughput.
Frequently asked questions
Why does the Field Test code not work on my iPhone?
Carrier configuration, calling features, device model or iOS behavior may prevent the dashboard from opening. Confirm the code and try while cellular service is active.
What is a good iPhone RSRP?
Around -90 dBm or stronger is often good received power, while below -110 dBm is generally weak. Quality and congestion still matter.
Can Field Test Mode find a tower location?
It can provide cell identifiers and measurements, but a tower database or map is still needed to associate them with a physical site.
Understand the network around you.
Explore nearby towers, signal context and real-world speed on iPhone.