user29266: I'm testing SIM800L module by registering to network manually and I'm getting an error message.
Here are the commands I tried.
AT+CSQ

+CSQ: 31,0

OK

AT+CBAND?

+CBAND: EGSM_MODE,ALL_BAND

OK



AT+COPS=?

+COPS: (1,"Bharat Karnataka","CellOne","40471"),(2,"Airtel","AIRTEL","40445"),(3,"Hutch-Kamataka","HUTCH","40486"),,(0-4),(0-2)

OK

AT+COPS=1,1,"40471"    

ERROR

AT+COPS=1,1,"40471"  is this command right? My 
SIM card is CellOne and it's 4G.
Power supply -7.4 li-ion 1100mAh battery with an adjustable 5V-5A buck converter(3.8v is supplied to SIM800L)

user49524: For the AT+COPS command you are setting manual with long alphanumeric network name but then using the numeric network name. Try AT+COPS=1,2,"40471"
REF
//Manually select T-mobile as carrier using short format alphanumeric network name
AT+COPS=1,0,"TMO"

//Manually select T-mobile as carrier using long format alphanumeric network name
AT+COPS=1,1,"T-Mobile USA"

//Manually select T-mobile as carrier using numeric network name
AT+COPS=1,2,"310260"


AT+CSQ checks the signal strength, you can check the reply range with a question mark,
AT+CSQ=?

+CSQ: (0-31,99),(0-7,99)

OK

The first number, 31, shows you have a good signal strength locally. 

AT+CBAND? shows the mobile operating band set

AT+COPS=? will search for networks, your response indicates you found a few. 

29266: <p>I'm testing SIM800L module by registering to network manually and I'm getting an <code>error</code> message.
Here are the commands I tried.</p>

<pre><code>AT+CSQ

+CSQ: 31,0

OK

AT+CBAND?

+CBAND: EGSM_MODE,ALL_BAND

OK



AT+COPS=?

+COPS: (1,"Bharat Karnataka","CellOne","40471"),(2,"Airtel","AIRTEL","40445"),(3,"Hutch-Kamataka","HUTCH","40486"),,(0-4),(0-2)

OK

AT+COPS=1,1,"40471"    

ERROR
</code></pre>

<p><code>AT+COPS=1,1,"40471"</code>  is this command right? My 
SIM card is CellOne and it's 4G.</p>

<p>Power supply -7.4 li-ion 1100mAh battery with an adjustable 5V-5A buck converter(3.8v is supplied to SIM800L)</p>
 49524: <p>For the <code>AT+COPS</code> command you are setting manual with long alphanumeric network name but then using the numeric network name. Try <code>AT+COPS=1,2,"40471"</code></p>

<p><a href="https://m2msupport.net/m2msupport/atcops-plmn-selection/" rel="nofollow noreferrer">REF</a></p>

<pre><code>//Manually select T-mobile as carrier using short format alphanumeric network name
AT+COPS=1,0,"TMO"

//Manually select T-mobile as carrier using long format alphanumeric network name
AT+COPS=1,1,"T-Mobile USA"

//Manually select T-mobile as carrier using numeric network name
AT+COPS=1,2,"310260"
</code></pre>

<hr>

<p><code>AT+CSQ</code> checks the signal strength, you can check the reply range with a question mark,</p>

<pre><code>AT+CSQ=?

+CSQ: (0-31,99),(0-7,99)

OK
</code></pre>

<p>The first number, 31, shows you have a good signal strength locally. </p>

<hr>

<p><code>AT+CBAND?</code> shows the mobile operating band set</p>

<hr>

<p><code>AT+COPS=?</code> will search for networks, your response indicates you found a few. </p>
