Different mobile networks have different ussds to perform certain functions,like checking airtime balance,checking data bundles among many other more.
Below are some of the ussds for different mobile service providers
MTN:To check your data balance on MTN you need to Text 2 to 131, or simply dial *559# or text 403 to 131.
And to check your MTN balance. Dial 141 from your cellphone for an update on your SMS and airtime. Alternatively you can check by dialing *141# for a summary, or *141*1# for a detailed balance and you will receive text message confirmation
For vodacom subscribers you need to dial *100# to check your airtime balance and *111# then follow the prompts to view your balance, buy bundles and transfer airtime.
TElkom mobile or 8ta:From your phone, dial *188#,You will then receive an SMS showing you how much data you have, how many voice minutes you have as well as how much Free Wifi you still have.
CELL C Subscribers:*101# Balance enquiry,*111*<mobile number># Send a Call Me Back message, *147*100# MSISDN query (retrieve own number). Alternatively, dial *147# and select option 3 or as a last resort SMS ‘bal’ or ‘balance‘ to 14302 and Cell C will automatically send you a SMS containing your remaining airtime, balance, check balance, mobile phone, mobile network, cellphone, cellc airtime balance