Quectel BG77: APN and network setup with an IoT SIM

Updated 27 October 2026

The Quectel BG77 is a cellular module for LTE-M and NB-IoT; it also has GNSS. With an IoT SIM, you set the APN with AT+CGDCONT=1,"IP","<apn>", choose the radio technology, then check that the module is registered, at home or in roaming. Vendor commands come from Quectel's manuals, standard ones from 3GPP TS 27.007; each cites its document.

Key facts

Quectel describes it as	Ultra-Compact LTE Cat M1/Cat NB2 Module
Radio technologies	LTE-M, NB-IoT
2G fallback	no
GNSS	yes
Form factor	LGA (SMT), 14.9 × 12.9 × 1.7 mm
Variants and regions	Global
Power saving	PSM: yes; eDRX: yes

Source: Quectel, BG77 product page. Checked 27 October 2026. Quectel's AT manuals carry a confidentiality notice: we cite them by title and page, without linking the files.

Set the APN

AT+CGDCONT=1,"IP","<apn>"

For the internal TCP/IP stack, Quectel sets the APN with AT+QICSGP=1,1,"<apn>","","",0 (Quectel BG95&BG77&BG600L Series TCP(IP) Application Note V1.5, page 14).

Source: Quectel BG95&BG77&BG600L Series AT Commands Manual V2.1, page 141.

Replace <apn> with the APN shown in your M2M.global account: the internet APN, or your private APN.

Choose the radio technology

AT+QCFG="iotopmode",0,1
AT+QCFG="nwscanseq",0203,1

iotopmode chooses the LTE category: 0 = LTE-M only, 1 = NB-IoT only, 2 = both. nwscanseq sets the search order with 02 = LTE-M, 03 = NB-IoT: 0203 searches LTE-M first. The module has no GSM. The final 1 applies the change at once.

Source: Quectel BG95&BG77&BG600L Series QCFG AT Commands Manual V2.1, pages 16 and 19.

Open the data connection

AT+QIACT=1

Activates context 1 of the internal TCP/IP stack.

Source: Quectel BG95&BG77&BG600L Series TCP(IP) Application Note V1.5, page 16.

Check that it works

AT+CPIN?        SIM ready? expect +CPIN: READY
AT+CEREG?       LTE registration: stat 1 = home network, 5 = roaming
AT+COPS?        network the module is using
AT+CGDCONT?     APN actually configured
AT+QCSQ

An IoT SIM that works in many countries is often registered in roaming: +CEREG: 0,5 is a valid, working registration. Firmware that waits only for status 1 (home network) never goes online on such a SIM. Status values come from 3GPP TS 27.007; the signal command from Quectel BG95&BG77&BG600L Series AT Commands Manual V2.1, page 87.

To save battery, request PSM with AT+CPSMS and eDRX with AT+CEDRXS (3GPP TS 27.007); the network decides which timers it grants.

Networks and shutdowns

LTE-M and NB-IoT run on 4G networks, but not every operator offers them, and roaming on them depends on agreements between operators. Check the coverage by country before you deploy.
No 2G or 3G dependency: the BG77 is not affected by 2G and 3G shutdowns.
Private delivery works with any module: the privacy is in the network path, not in the device. See private delivery.

The SIM: IoT SIM cards and IoT eSIM. All commands explained: AT commands.

Frequently asked questions

How do I set the APN on the Quectel BG77?

Send AT+CGDCONT=1,"IP","<apn>", with the APN of your SIM in place of <apn>. Source: Quectel BG95&BG77&BG600L Series AT Commands Manual V2.1.

Does the Quectel BG77 support LTE-M and NB-IoT?

Quectel states both for the BG77: LTE-M and NB-IoT.

Does the Quectel BG77 fall back to 2G?

No. The BG77 has no 2G fallback, so 2G shutdowns do not affect it.

Why does my BG77 show +CEREG: 0,5?

Status 5 means registered in roaming, a normal working state for an IoT SIM that uses partner networks. Treat it like status 1 (home network) in your firmware.