I am using Digi dev board XBIB-CU-TH, the modem is XBee3 LTE-M/NB-IoT, which has been loaded with the Digi Regulatory Firmware F1416. The firmware works pretty well with the Bluetooth DTM testing. The cellular testing, on the other hand, has been very troublesome in the Transparent Mode. I then switch to the USB Direct Mode, so I can use the u-blox m-center software to conduct the test by directly interacting with the SARA R410M module.
My question is - The Regulatory Firmware offers a "modulated transmit" test with a specific UL EARFCN and power settings. The u-blox has something called "non-signaling mode" transmit test with a specific EARFCN and power level as well. Are these two functions the same? I know the observations from my spectrum analyzer are different. Using u-blox m-center, I can issue a non-signaling transmit on channel, for example, 19950 (band 4), and get a nice frequency distribution centered at 1710 MHz. The "modulated transmit", same channel and power, I couldn't see anything on the spectrum analyzer.
In case you ask - No, I don't have a callbox.