diff --git a/resources/templates/provision/yealink/t21p/{$mac}.cfg b/resources/templates/provision/yealink/t21p/{$mac}.cfg
index d8f4e2c6e9..964bcedf88 100644
--- a/resources/templates/provision/yealink/t21p/{$mac}.cfg
+++ b/resources/templates/provision/yealink/t21p/{$mac}.cfg
@@ -669,7 +669,11 @@ account.2.out_dialog_blf_enable = 0
 ##account.X.shared_line =
 
 #Assign account1 as shared line; 0-Disabled (default), 1-Broadsoft SCA, 2-BLA;
-account.2.shared_line =
+{if isset($shared_line_2) }
+account.2.shared_line = {$shared_line_2}
+{else}
+account.2.shared_line = 0
+{/if}
 
 #Configure BLA number for account1 and the subscribe period (in seconds). It ranges from 60 to 7200, the default value is 300.
 account.2.bla_number =
@@ -1173,7 +1177,11 @@ account.3.out_dialog_blf_enable = 0
 ##account.X.shared_line =
 
 #Assign account1 as shared line; 0-Disabled (default), 1-Broadsoft SCA, 2-BLA;
-account.3.shared_line =
+{if isset($shared_line_3) }
+account.3.shared_line = {$shared_line_3}
+{else}
+account.3.shared_line = 0
+{/if}
 
 #Configure BLA number for account1 and the subscribe period (in seconds). It ranges from 60 to 7200, the default value is 300.
 account.3.bla_number =
@@ -1660,7 +1668,11 @@ account.4.out_dialog_blf_enable = 0
 ##account.X.shared_line =
 
 #Assign account1 as shared line; 0-Disabled (default), 1-Broadsoft SCA, 2-BLA;
-account.4.shared_line =
+{if isset($shared_line_4) }
+account.4.shared_line = {$shared_line_4}
+{else}
+account.4.shared_line = 0
+{/if}
 
 #Configure BLA number for account1 and the subscribe period (in seconds). It ranges from 60 to 7200, the default value is 300.
 account.4.bla_number =
@@ -2146,7 +2158,11 @@ account.5.out_dialog_blf_enable = 0
 ##account.X.shared_line =
 
 #Assign account1 as shared line; 0-Disabled (default), 1-Broadsoft SCA, 2-BLA;
-account.5.shared_line =
+{if isset($shared_line_5) }
+account.5.shared_line = {$shared_line_5}
+{else}
+account.5.shared_line = 0
+{/if}
 
 #Configure BLA number for account1 and the subscribe period (in seconds). It ranges from 60 to 7200, the default value is 300.
 account.5.bla_number =
@@ -2631,7 +2647,11 @@ account.6.out_dialog_blf_enable = 0
 ##account.X.shared_line =
 
 #Assign account1 as shared line; 0-Disabled (default), 1-Broadsoft SCA, 2-BLA;
-account.6.shared_line =
+{if isset($shared_line_6) }
+account.6.shared_line = {$shared_line_6}
+{else}
+account.6.shared_line = 0
+{/if}
 
 #Configure BLA number for account1 and the subscribe period (in seconds). It ranges from 60 to 7200, the default value is 300.
 account.6.bla_number =