diff --git a/examples/sample.source.TAP3/Makefile b/examples/sample.source.TAP3/Makefile
index 7458688..4dd100c 100644
--- a/examples/sample.source.TAP3/Makefile
+++ b/examples/sample.source.TAP3/Makefile
@@ -724,6 +724,23 @@
 	diff ./.tmp.1.$$ ./.tmp.2.$$ || exit 2; \
 	rm -f ./.tmp.[12].$$; \
 	done; fi
+	@if test -f ./sample-DataInterChange-1.xer ; then \
+	for f in ./sample-DataInterChange-*.xer; do \
+	echo "Recoding $$f into DER and back..."; \
+	./${TARGET} -ixer -oder $$f > ./.tmp.1.$$ || exit 2; \
+	./${TARGET} -iber -oxer ./.tmp.1.$$ > ./.tmp.2.$$ || exit 2; \
+	diff $$f ./.tmp.2.$$ || exit 2; \
+	rm -f ./.tmp.[12].$$; \
+	done; fi
+	@if test -f ./sample-DataInterChange-1.per ; then \
+	for f in ./sample-DataInterChange-*.per; do \
+	echo "Recoding $$f into DER into XER and back..."; \
+	./${TARGET} -iper -oder $$f > ./.tmp.1.$$ || exit 2; \
+	./${TARGET} -ider -oxer ./.tmp.1.$$ > ./.tmp.2.$$ || exit 2; \
+	./${TARGET} -ixer -oper ./.tmp.2.$$ > ./.tmp.1.$$ || exit 2; \
+	diff $$f ./.tmp.1.$$ || exit 2; \
+	rm -f ./.tmp.[12].$$; \
+	done; fi
 	@echo ================
 	@echo All tests passed
 	@echo ================