How to pair in wireless SPP vs FAST the differences and similarities between the pairing process for SPP (Serial Port Profile) and FAST. Although these two profiles are commonly used for a variety of applications, the focus of this guide is on the implications related to using Serialio’s scanners in either SPP and FAST modes.  The most important difference when switching between FAST and SPP is that you CANNOT pair through your device’s wireless settings app while using FAST mode. Below are basic instructions on how to pair your wireless scanner