It is recommended to setup an auto top up and a Data pack add on that is renewing every month regardless of which SIM you are using.
CBSYS device usually takes less than 100MB of Data per month, hence any data add-on providing 100MB per month will be sufficient for sending the data to server.
Here is an example of how to setup auto top-up and activate the data pack add-on in 2 Degrees,
Step 1. Go to my 2degrees
Step 2. Select Mobile Log in
Step 3. Login using your registered id & password
Step 4. Select the number for further setup
Step 5. Check the account and data credit balance here, click "Top up now" button to enter top up page
Step 6. Click "Auto top up" and enter all the details required including the credit card information.
Step 7. When top up is completed, click "Add-on" from the top menu , then click "Add a Data Pack"
Step 8. Choose $6 100 MB as this is enough for the device to send the data.
Step 9. Go back to Dashboard and check the balance again.
Step 10. Scroll down to see the data pack renewal date.
If you are using Spark, Skinny, or vodafone, please visit their website for how to auto top up and purchasing add-on data.