Converting to a TTL signal?
You have a 5V swing and undefined grounds for isolation or not with unknown source impedances or voltage/current shift.

An Opto isolator may be the ideal choice for isolation and level shifting with pullup R on input and output to determine input and output current  limits.  THere are thousands to choose from.  But you indicated non-inverting logic so choose a non-inverting output or add a logic inverter.

Otherwise, a cheap and dirty method is to use a Common base transistor biased at 12V with a zener and series R to Vb and input 9~14V on Ve and output on Vc with a pullup to 5V goes to 0 to 5V.







simulate this circuit &ndash; Schematic created using CircuitLab

https://www.digikey.com/products/en/isolators/optoisolators-logic-output/902