| Commands | What does it do? | Sample Reponses |
| AT | Same thing as “Hey!” in real life. This is used to check if you are able to communicate with the device. | OK |
| AT+COPS=? | To see all available carriers. This command will also filter out carriers that are not compatible with the SIM card. | 0, 1, “T-Mobile” or 0, 4, “AT&T” |
| AT+COPS = (#, #) | Check the current network. Obtain two #‘s from the above command. For example, if you want to connect to T-Mobile, you would do AT+COPS=(0,1). | ”T-Mobile” or “AT&T” |
| AT+CCID | Check the SIM ID IMEI NUMBER | OK |
| AT+CREG? | Network Registration Status. You can run the AT+CREG=? for available flags.(#, “Current Network Name”, PLMN #) | OK |
| AT+COPS=? | List of available networks. This response is valuable to switch carriers. | (4, “Network Name”, PLMN #), (2, “Network Name 2”, PLMN #2) … |
| AT+COPS = 1, 0 “Carrier Name” | Manually connect to a network. This is also known as PLMN selection. | If all went well, you should get an OK response. If there is an error, it will reply back with CME ERROR. The error usually occurs if your provider’s SIM does not support the carrier you are connecting to. Please check with your wireless provider on the list of providers that is supported in your area. |
| AT+BANDS | Manually select a cellular band. This shouldn’t be used often unless you are having issues with network congestion. The numbers seen in the sample result is different for every device. | OK 0100004000 B12 045000000 B5 |