MTK helio x20 Mediatek MT6797x CARBAYTA tablet no mobile network bars or calls

[learnmobile]

Tablet recognizes sim but doesn't show network bars & doesn't connect to any mobile network to make calls /SMS or data.
Usually, the SIM card which I put in the tablet the apn for that carrier comes up automatically as it can read the carrier but just doesn't bring them in the list of networks available. A couple of networks comes of another carrier of 2g or 3g (forbidden) written in front of them & the network which comes can't connect to them.

it gives some kind of driver for Mediatek MT6797x (the chip I have in my tablet of CARBAYTA Processor Manufacturer: MTK helio x20 Screen size: 11.6 inch
Network: 4G TLE & WIFI, CPU: MTK 6797, 10 cores

When phonedoctor ran to test call function:
it ran: The system will test the connection to the mobile network operator automatically: Network operator, Network name, Access Technology, Support VOIP: = all came blank but in the main menu where call function is there, it gave a green checkmark & today's date.

In Cellular Network option when ran :
Turn off Wi-fi, Turn on mobile data and make sure you're connected to your mobile network. Press the [start] below to start the test.
Check chip : ok , Public Ip: x , Check error packet : 0

Public ip had a red cross sign.
when back to the main menu Cellular Network option had a red cross in a circle.

Seems like it can't read the apn settings of the current mobile carrier or not able to connect to the mobile tower nearby.
But when I ran some other apn settings app it does read the nearby power & some information I get is as follows :

Current network :
Signal strength : -93dbm 26 asu
Voice service : Emergency calls only
Data Service : Disconnected
Voice Network Type : Unknown
Data Network Type : Unknown
Voice call status : idle
Roaming : Not roaming
Set preferred Network type : LTE /TD-SCDMA/UMTS
run ping test : fail
ping Hostname (####google####) IPv4 : Fail(2)
ping Hostname (####google$###) IPv6 : Fail(2)
HTTP Client Test : Fail: IOException

Data Connection Real Time info:
Message Waiting : false
Call Redirect : false
Data sent : 0pkts, 0 bytes
Data Received : 0pkts, 0 bytes
Number of PPP Reset Since Boot :
Mobile Radio Power - checked
VoLTE provisioned - checked
Video Calling Provisioned - checked

SMSC : (+###-###-####) (brings up a mobile number of nearby tower when freshed.

Toggle DNS Check : 0.0.0.0 allowed

Cell info refresh rate (deprecated): choose immediate
Neighbor Cell info (deprecated) No neighboring cells

ALL Cell mesurement info
WCDMA

SRV MCC MNC LAC CID UARFCN PSC RSCP
s 404 11 30041 68536 10757 53 -49
404 11 30041 68536 10757 53 -49

Above is some info i was able to get from some apn testing software.
Please let me know how can I get at least basic calls /SMS functions to work & tablet to get mobile bars. Tablet is without mobile network bars.

I do appreciate in advance if you can put me in the right path to get network bars.
Thanks

 

[B. Diddy]

Welcome to Android Central! The key thing here is if the device supports the network bands of the carrier you're using. Which carrier are you using? I'm also trying to find the specs for your device showing the network bands it supports, but so far I haven't found that info.

 

[learnmobile]

@B. Diddy , Thanks for helping out. much appreciated.
I have attached some of the band info from tablet through MTK engineering app. I am using in India Vodfone, idea, Jio, Airtel. so i have these four sims which work in all 4g mobiles. I won't mind if these 4g sis can give atleast a call function. Can't even make calls because they find not connected to mobile network, only in some ways i do get for emergency calls only. Seller in china posted a video in which he showed that 4g sim is working so either the device is defected or somehow i am missing something evident. It does read the carried whose sim i put in while choosing the sim 1/2 from the list for data. it does shows idea or vodafone sim, but network bars are blank. Thanks for your help.

 

[learnmobile]

some more band info through Network Cell info app. Hope it gives you some info on my network available. thanks

 

[B. Diddy]

It looks like the main LTE bands used in India are 3, 5, and 40: https://www.nepalitelecom.com/2017/02/frequency-bands-2g-3g-4g-mobile-india.html. Of those, your device only supports band 3, so if your nearby towers don't use band 3, you wouldn't be able to get LTE. I'm not sure why you can't get 3G, though. Can you change the Preferred Network Type to force 3G/UMTS onlyl?

Do you know if your device was originally sold through a carrier? If so, the device could be carrier-locked, and therefore wouldn't allow you to use a different carrier's SIM.