Can someone explain how command AT+QCFG="band" works?(ec200t)

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