I am sending the command AT+QCFG="band" and in response, I get: +QCFG: "band",0x93,0x1a0080800c5 What does this value mean?
also while there is that value it may change working bands on its own, and the value itself (0x1a0080800c5) won’t change, I can track it with the command AT+QNWINFO, so is it some auto mode?
Bandmasks control the currently supported bands on a modem. The native bandmasks of a particular modem model can be restricted further by removing values, but bands not supported by the modem firmware cannot be added.
The “0x93” is your GW bandmask (for 2G/GSM and 3G/WCDMA) bands.
That’s decoded from a lookup table, where 0x93 decodes as GSM 900 + GSM 1800 + WCDMA 2100 MHz + WCDMA 900 MHz.
00000001 GSM 900 MHz
00000002 GSM 1800 MHz
00000004 GSM 850 MHz
00000008 GSM 1900 MHz
00000010 WCDMA 2100 MHz
00000020 WCDMA 1900 MHz
00000040 WCDMA 850 MHz
00000080 WCDMA 900 MHz
00000100 WCDMA 800 MHz
00000200 WCDMA 1700 MHz
0000FFFF Any frequency band
0x1a0080800c5 is the 4G/LTE bandmask. This is decoded by an algorithm where the bands are enabled if and only if the corresponding bit is set.
In binary, 0x1a0080800c5 is 00011010000000001000000010000000000011000101.
Bit 1 is the rightmost bit, meaning bits 1, 3, 7, 8, 20, 28, 38, 40 and 41 are set. So these are the LTE band numbers supported by that bandmask.
There’s a script on pastebin.com to encode lists of LTE or NR5G band numbers into the relevant bandmask: encodemask - Pastebin.com
In use:
encodemask 1 3 7 8 20 28 38 40 41
0000000000000000000001A0080800C5
thanks. do you know by the way how module chooses its band? because on one antenna it connects to LTE band 20 and on another LTE band 3 for example.
There are several factors involved.
The channel used for the serving cell is negotiated between modem and tower. The channel selected determines the band.
Factors include received signal strength and quality, and the relative priorities for channels/bands set (and broadcast) by the network provider.
There are other relevant priorities written on the SIM.