No alternate available since the Surface line opted to use proprietary connector instead of USB - C. (microsoft.com)
On the other edge is the same sort of proprietary connector that sits on the tablet's bottom — to let you charge the Infinity while it's in its laptop - like state. (trustedreviews.com)
For instance, the two dots on the tablet's rear are supposedly proprietary connectors for Samsung's book cover. (pocket-lint.com)