| Tool | Purpose | |------|---------| | | Capture & limited analysis | | QCAT | Advanced analysis, filtering, export | | QCS (Qualcomm Capture Service) | On-device logging without PC | | QPSD (Qualcomm Protocol Sniffer) | Real-time message decoding | | Open source | None fully capable; qcom-diag (partial) |
Initial Access Logs , SIB Decode, and RACH Logs.
| Log Code (Hex) | Meaning | |----------------|---------| | 0x4040 | LTE RRC OTA message (DL/UL) | | 0x4050 | LTE RRC state machine | | 0x4120 | LTE MAC scheduler | | 0x5001 | NAS EMM state | | 0x5101 | NAS ESM (bearer) | | 0x6000 | WCDMA RRC | | 0x7000 | GSM RR | | 0x8000 | TCP/IP stats | | 0xB015 | RF NV (NV items) | qxdm log
These vary by QXDM version and chipset (e.g., Snapdragon X55, X65, X70).
| Feature | QXDM Log | Android Logcat | Modem ELF/Dumps | Air Interface (pcap) | |---------|----------|----------------|----------------|----------------------| | | L1–L3, modem internal | Apps, kernel, HAL | Crash analysis | L3 OTA only | | Tool | QXDM / QCAT | logcat | Crashdump parser | Wireshark | | Real-time | Yes | Yes | No | Yes (with root) | | Decode needed | Full (proprietary) | Text | Binary (vendor) | Standardized | | Use case | Modem debug | System debug | Fatal errors | Network validation | | Tool | Purpose | |------|---------| | |
| Feature | Description | |---------|-------------| | | Binary ( .isf , .dmb , .qmdl , .dlf ) | | Size | Can be gigabytes per hour, depending on enabled items | | Real-time | Streamed live over USB or stored in device RAM | | Encoding | Uses TLV (Type-Length-Value) with proprietary message IDs | | Security | Often encrypted or compressed; requires Qualcomm license to decode |
(Qualcomm eXtensible Diagnostic Monitor) is a proprietary software tool developed by Qualcomm. It is used for debugging, logging, and analyzing the behavior of Qualcomm-based modems (cellular basebands) found in most Android smartphones, IoT modules, and many other wireless devices. It is used for debugging, logging, and analyzing
Analyzing QXDM logs requires a strong understanding of the 3GPP specification (LTE/5G-NR) stack. The log itself is a black box of timestamps and hex codes until filtered correctly.