I dont know if you're asking about a specific vendor's cable, or in general. If it's a specific vendor just email their technical support.
In general -- Section 6.4 (page 9) of standard SAE J2534-1 defines the maximum cable length between PassThru device and vehicle as five meters. In reality, some vehicles or low-quality interfaces may require a much shorter cable.
Six feet is typical. Many vendors supply one like this with their hardware: OBD II Cable
High quality 6-foot (1.8 meters) OBDII Cable Type C (J1962 to DB9F), with molded connectors and strain relief. Works with all of our OBD-II interfaces, as well as interfaces made by other scan tool manufacturers such as AutoTap.
That gets you from the car's port to the interface. Then you use a serial cable to get from the interface to the PC. RS232 spec usually allows up to 50 feet without any special stuff.
Next time put a little more thought into the question you ask and you will likely get better answers.