diff --git a/src/odoors/ODCore.c b/src/odoors/ODCore.c
index e6943b92d720398b51151b09483f70ae1a51fa81..f69e79ca1aec02fc77580e9ab7da89725b4eec56 100644
--- a/src/odoors/ODCore.c
+++ b/src/odoors/ODCore.c
@@ -806,7 +806,7 @@ cleanup:
  *
  *     Return: void
  */
-ODAPIDEF void ODCALL od_disp(char *pachBuffer, INT nSize, BOOL bLocalEcho)
+ODAPIDEF void ODCALL od_disp(const char *pachBuffer, INT nSize, BOOL bLocalEcho)
 {
    /* Log function entry if running in trace mode. */
    TRACE(TRACE_API, "od_disp()");
diff --git a/src/odoors/OpenDoor.h b/src/odoors/OpenDoor.h
index 3091d70e08540834021c0d6901ffebdeb2651ea3..b0a1252b9e5538bbe79ad24be125a101615de2df 100644
--- a/src/odoors/OpenDoor.h
+++ b/src/odoors/OpenDoor.h
@@ -959,7 +959,7 @@ ODAPIDEF void ODCALL   od_clr_line(void);
 ODAPIDEF void ODCALL   od_clr_scr(void);
 ODAPIDEF BYTE ODCALL   od_color_config(char *pszColorDesc);
 ODAPIDEF tODControl *  ODCALL od_control_get(void);
-ODAPIDEF void ODCALL   od_disp(char *pachBuffer, INT nSize, BOOL bLocalEcho);
+ODAPIDEF void ODCALL   od_disp(const char *pachBuffer, INT nSize, BOOL bLocalEcho);
 ODAPIDEF void ODCALL   od_disp_emu(const char *pszToDisplay, BOOL bRemoteEcho);
 ODAPIDEF void ODCALL   od_disp_str(const char *pszToDisplay);
 ODAPIDEF BOOL ODCALL   od_draw_box(BYTE btLeft, BYTE btTop, BYTE btRight,