diff --git a/doc/c128.sgml b/doc/c128.sgml
index 1bdcf01f5..feda1cbba 100644
--- a/doc/c128.sgml
+++ b/doc/c128.sgml
@@ -124,6 +124,7 @@ declaration and usage.
 <item>cbm_k_basin
 <item>cbm_k_bsout
 <item>cbm_k_clrch
+<item>cbm_k_tksa
 <item>cbm_load
 <item>cbm_open
 <item>cbm_opendir
diff --git a/doc/c16.sgml b/doc/c16.sgml
index 27938ff1e..6375a7898 100644
--- a/doc/c16.sgml
+++ b/doc/c16.sgml
@@ -115,6 +115,7 @@ declaration and usage.
 <item>cbm_k_basin
 <item>cbm_k_bsout
 <item>cbm_k_clrch
+<item>cbm_k_tksa
 <item>cbm_load
 <item>cbm_open
 <item>cbm_opendir
diff --git a/doc/c64.sgml b/doc/c64.sgml
index a18ce359f..b04b40508 100644
--- a/doc/c64.sgml
+++ b/doc/c64.sgml
@@ -217,6 +217,7 @@ declaration and usage.
 <item>cbm_k_basin
 <item>cbm_k_bsout
 <item>cbm_k_clrch
+<item>cbm_k_tksa
 <item>cbm_load
 <item>cbm_open
 <item>cbm_opendir
diff --git a/doc/cbm510.sgml b/doc/cbm510.sgml
index b171c2ce3..1e6a4e07b 100644
--- a/doc/cbm510.sgml
+++ b/doc/cbm510.sgml
@@ -118,6 +118,7 @@ declaration and usage.
 <item>cbm_k_basin
 <item>cbm_k_bsout
 <item>cbm_k_clrch
+<item>cbm_k_tksa
 <item>cbm_load
 <item>cbm_open
 <item>cbm_opendir
diff --git a/doc/cbm610.sgml b/doc/cbm610.sgml
index 790983b3d..9f963dbd5 100644
--- a/doc/cbm610.sgml
+++ b/doc/cbm610.sgml
@@ -121,6 +121,7 @@ declaration and usage.
 <item>cbm_k_basin
 <item>cbm_k_bsout
 <item>cbm_k_clrch
+<item>cbm_k_tksa
 <item>cbm_load
 <item>cbm_open
 <item>cbm_opendir
diff --git a/doc/funcref.sgml b/doc/funcref.sgml
index f10379c93..0fe1ce847 100644
--- a/doc/funcref.sgml
+++ b/doc/funcref.sgml
@@ -203,6 +203,7 @@ function.
 <item><ref id="cbm_k_setlfs" name="cbm_k_setlfs">
 <item><ref id="cbm_k_setnam" name="cbm_k_setnam">
 <item><ref id="cbm_k_talk" name="cbm_k_talk">
+<item><ref id="cbm_k_tksa" name="cbm_k_tksa">
 <item><ref id="cbm_k_udtim" name="cbm_k_udtim">
 <item><ref id="cbm_k_unlsn" name="cbm_k_unlsn">
 <!-- <item><ref id="cbm_load" name="cbm_load"> -->
@@ -2284,6 +2285,28 @@ only be used in presence of a prototype.
 </quote>
 
 
+<sect1>cbm_k_tksa<label id="cbm_k_tksa"><p>
+
+<quote>
+<descrip>
+<tag/Function/Send TALK secondary address to serial bus
+<tag/Header/<tt/<ref id="cbm.h" name="cbm.h">/
+<tag/Declaration/<tt/void __fastcall__ cbm_k_tksa (unsigned char addr);/
+<tag/Description/This function transmits a secondary address on the serial bus for a TALK device.
+<tag/Notes/<itemize>
+<item>The function is only available as fastcall function, so it may
+only be used in presence of a prototype.
+<item>The function can only be called after a call to TALK.
+<item>The function will not work after a LISTEN.
+</itemize>
+<tag/Availability/cc65
+<tag/See also/
+<ref id="cbm_k_talk" name="cbm_k_talk">
+<tag/Example/None.
+</descrip>
+</quote>
+
+
 <sect1>cbm_k_udtim<label id="cbm_k_udtim"><p>
 
 <quote>
diff --git a/doc/plus4.sgml b/doc/plus4.sgml
index c1b6165f6..333bd879a 100644
--- a/doc/plus4.sgml
+++ b/doc/plus4.sgml
@@ -113,6 +113,7 @@ declaration and usage.
 <item>cbm_k_basin
 <item>cbm_k_bsout
 <item>cbm_k_clrch
+<item>cbm_k_tksa
 <item>cbm_load
 <item>cbm_open
 <item>cbm_opendir
diff --git a/doc/vic20.sgml b/doc/vic20.sgml
index a61691733..1744a2b90 100644
--- a/doc/vic20.sgml
+++ b/doc/vic20.sgml
@@ -99,6 +99,7 @@ declaration and usage.
 <item>cbm_k_basin
 <item>cbm_k_bsout
 <item>cbm_k_clrch
+<item>cbm_k_tksa
 <item>cbm_load
 <item>cbm_open
 <item>cbm_opendir
diff --git a/include/cbm.h b/include/cbm.h
index 1395f700f..fbf8d555a 100644
--- a/include/cbm.h
+++ b/include/cbm.h
@@ -204,6 +204,7 @@ void __fastcall__ cbm_k_setlfs (unsigned char LFN, unsigned char DEV,
                                 unsigned char SA);
 void __fastcall__ cbm_k_setnam (const char* Name);
 void __fastcall__ cbm_k_talk (unsigned char dev);
+void __fastcall__ cbm_k_tksa (unsigned char addr);
 void cbm_k_udtim (void);
 void cbm_k_unlsn (void);
 void cbm_k_untlk (void);
diff --git a/libsrc/cbm/c_tksa.s b/libsrc/cbm/c_tksa.s
new file mode 100644
index 000000000..b818d7205
--- /dev/null
+++ b/libsrc/cbm/c_tksa.s
@@ -0,0 +1,12 @@
+;
+; Bas Wassink, 22.05.2018
+;
+; void __fastcall__ cbm_k_tksa (unsigned char addr)
+;
+
+
+        .import TKSA
+        .export _cbm_k_tksa
+
+_cbm_k_tksa = TKSA
+