diff --git a/src/system/impold.wthncp b/src/system/impold.wthncp
index 4709a9c1..7f48e5be 100755
--- a/src/system/impold.wthncp
+++ b/src/system/impold.wthncp
@@ -695,6 +695,23 @@ FNDHS5:	MOVEM I,IMPHTF		;FREE LIST
 	SKIPGE IMPHTF
 	 POPJ P,		;GC-OVERFLOW
 	JRST FNDHST		;TRY AGAIN, SHOULD WIN
+
+;See if IMP code is willing to handle a particular datagram right now.
+; A/ IP DGM pointer
+; C/ Immediate destination address
+; Returns +1, can't send right now, +2, OK to send
+;
+IMPCTS:
+IFN 0,[
+	MOVE T,C		;Set up for FNDHST
+	AND T,[<377_16.>+377]	;Mask out all but host and IMP field
+	CALL FNDHST		;Get host index in H
+	 POPJ P,		;No host entry, don't send
+	JSP T,IMPBLI		;See if OK to send
+	 POPJ P,		;IMP wants to block, no send
+]
+	JRST POPJ1		;Skip return if OK to send.
+
 
 SUBTTL	ARPANET INPUT INTERRUPT LEVEL