CSV means comma separated values. It's like a normal "txt" file with commas at regular places to separate some values. Typically the first line of CSV file is a "header", containing names of columns ...
Library is based on M2M_Quectel libary from M2M solutions AB and partialy on AT-command-library from Timothy Woo. Library is using UART line to send AT commands to the Quectel module. Some basic logic ...