When working with AT Interface firmware, what is the correct syntax to use the AT+LSCN command when not wanting to use all the optional parameters?

As per the AT Interface User Guide, the AT+LSCN has four parameters, all of which are optional: timeout, escape pattern, rssi, and scan type, using the following syntax:

AT+LSCN <,scanType>>>>

Therefore, the correct syntax for AT+LSCN without using all optional parameters would be to leave the unused parameters blank (not a "0", just blank) while still dividing each of the optional parameters using commas. For example, if the only parameter required is to configure it the scan type (last parameter) to enable scanning for 1M and Coded PHY (256k) with extended advertisements you would use the following syntax:

AT+LSCN ,,,7

Please see the AT Interface User Guide for the module you are working with for more information.

Lyra Series Modules – AT Interface User Guide

BL65x Series Modules – AT Interface User Guide