设置了234G
Type Index Time Local Time Module Message Comment Time Different
SYS 129283 8144 20:22:02:025 NIL [AT_I p21, s11]AT+ERAT=6,0
SYS 140891 8279 20:22:02:625 NIL [AT_I p21, s11]AT+ERAT=6,0
SYS 141992 8285 20:22:02:625 NIL [AT_I p21, s11]AT+ERAT=6,0
SYS 146238 8323 20:22:02:825 NIL [AT_I p21, s11]AT+ERAT=6,0
SYS 159189 8618 20:22:04:260 NIL [AT_I p21, s11]AT+ERAT=6,0
SYS 160421 8684 20:22:04:685 NIL [AT_I p21, s11]AT+ERAT=6,0
SYS 162356 8810 20:22:05:285 NIL [AT_I p21, s11]AT+ERAT=6,0
先设置了2G only，再设置了23G
Type Index Time Local Time Module Message Comment Time Different
SYS 131007 8356 20:30:11:990 NIL [AT_I p21, s11]AT+ERAT=0,0
SYS 207469 42720 20:33:03:970 NIL [AT_I p21, s11]AT+ERAT=2,0
设置了23G
Type Index Time Local Time Module Message Comment Time Different
SYS 128067 8318 10:55:18:910 NIL [AT_I p21, s11]AT+ERAT=2,0
SYS 130955 8456 10:55:19:610 NIL [AT_I p21, s11]AT+ERAT=2,0
SYS 131705 8461 10:55:19:610 NIL [AT_I p21, s11]AT+ERAT=2,0
SYS 135234 8486 10:55:19:610 NIL [AT_I p21, s11]AT+ERAT=2,0
SYS 146759 8770 10:55:21:010 NIL [AT_I p21, s11]AT+ERAT=2,0
SYS 150560 8872 10:55:21:610 NIL [AT_I p21, s11]AT+ERAT=2,0
SYS 152041 8961 10:55:22:015 NIL [AT_I p21, s11]AT+ERAT=2,0
由于AP log较多，通查了所有AP log，发现有三次手动设置优选网络，但是没有发现仅3G的设置：
//---> 2/3G模式：Phone.NT_MODE_WCDMA_PREF = RILConstants.NETWORK_MODE_WCDMA_PREF = 0 /* GSM/WCDMA (WCDMA preferred) */
12-25 10:53:58.741969 1243 1243 D NetworkSettings: [onPreferenceChangeMTK] preference = Preferred network type
12-25 10:53:58.742491 1243 1243 D NetworkSettings: buttonNetworkMode: 0
//---> 2/3G模式：Phone.NT_MODE_WCDMA_PREF = RILConstants.NETWORK_MODE_WCDMA_PREF = 0 /* GSM/WCDMA (WCDMA preferred) */
12-25 10:53:58.741969 1243 1243 D NetworkSettings: [onPreferenceChangeMTK] preference = Preferred network type
12-25 10:53:58.742491 1243 1243 D NetworkSettings: buttonNetworkMode: 0
//--->仅 2G模式：Phone.NT_MODE_GSM_ONLY = RILConstants.NETWORK_MODE_GSM_ONLY = 1 /* GSM only */
01-01 20:28:53.202789 1238 1238 D NetworkSettings: [onPreferenceChangeMTK] preference = Preferred network type
01-01 20:28:53.203265 1238 1238 D NetworkSettings: buttonNetworkMode: 1
另外，如果想设置仅3G模式，AP侧应该设置的值是2：
Phone.NT_MODE_WCDMA_ONLY = RILConstants.NETWORK_MODE_WCDMA_ONLY = 2; /* WCDMA only */