Subsource can be configured in order to monitor marketing campaigns or how business comes to the hotel. Many hotels want to monitor their business based on advertisements, walk-in, local and third party campaigns. By categorizing each booking into a subsource, it allows the hotel to have statistical data on each subsource. The subsource picklist is customizable per property. Although in multi-property environments, we'd suggest using the same subsource list. It is advisable to make the Subsource field a mandatory field on the reservation screen. See Mandatory Field This will then link every reservation to a Subsource. Many statistical reports are available for Subsource Codes. See File->Reports->Statistics& Forecasts (Statistics per day, per period and MTD/YTD)
To create the Subsource Code picklist, go to Settings->Statistics->Subsource Code
To add a new Subsource Code, select the 
Subsource- Enter the Subsource Code alphanumeric and limited to 8 characters.
Description - Enter the description (max. 30 characters.
To Translate to another language, select the ... in the description field.
Back office suffix - Used to identify sources for certain back office interfaces that handle source statistics.
In picklist - If checked, the Subsource Code will appear in the picklist on the reservation screen.
List Order- The default list order is alphabetical unless a value is listed here. Based on the value, the subsource codes will then appear in that order. If using the list order, a number needs to be assigned to each subsource code.
Nis Code - This is used to group Subsource Codes together for the purpose of certain back office interfaces that handle statistics.
Save using the green checkmark.