Looking for SMS service providers for C4C and Hybris Marketing(On-Premise) other than SAP SMS 365

We have checked that "SAP SMS 365" is the SMS provider available out of box for C4C and Hybris Marketing onpremise(1702). Is there any service provider that can be used other than "SAP SMS 365" which could be integrated with our C4C application and Hybris marketing system?

If there are any, please post the names. What could be the code effort required for using the other SMS provider in Hybris marketing?