Field Test Mode changes over time
Apple, carriers and modem versions can expose different menus and measurements. A missing value does not necessarily mean that the network lacks that metric.
Start with the serving-cell reading
When several values appear, look for the serving-cell or primary-cell section. Record the network type and timestamp so later comparisons use the same context.
Compare locations, not isolated numbers
A controlled comparison between rooms, outdoors and different times is more useful than one screenshot. Use the same device and network mode when possible.
Frequently asked questions
How do I open Field Test Mode on iPhone?
The commonly used dialer code is *3001#12345#*. Available menus vary by iPhone, iOS version and carrier.
Why can I not find RSRQ or SINR?
The carrier, modem and current network mode determine which measurements appear. Some iPhone configurations expose only part of the radio data.
Does Field Test Mode identify the exact tower?
It can expose cell and radio information, but matching that information to a physical tower still depends on available network and tower data.