diff --git a/htdocs/install/mysql/tables/llx_c_type_contact.sql b/htdocs/install/mysql/tables/llx_c_type_contact.sql
index 65ddb592ce0..2b309be4445 100644
--- a/htdocs/install/mysql/tables/llx_c_type_contact.sql
+++ b/htdocs/install/mysql/tables/llx_c_type_contact.sql
@@ -31,7 +31,7 @@ create table llx_c_type_contact
 (
   rowid      	integer     AUTO_INCREMENT PRIMARY KEY,
   element       varchar(64) NOT NULL,
-  source        varchar(8)  DEFAULT 'external' NOT NULL,
+  source        varchar(8)  DEFAULT 'external' NOT NULL,    -- 'internal' (for link object-user) or 'external' (for link object-third party)
   code          varchar(32) NOT NULL,
   libelle 	    varchar(128)	NOT NULL,
   active  	    tinyint DEFAULT 1  NOT NULL,