diff --git a/crontab_test.go b/crontab_test.go
index 78ce2f8..8a32427 100644
--- a/crontab_test.go
+++ b/crontab_test.go
@@ -79,7 +79,7 @@ func TestParseIntervalPlus(t *testing.T) {
 
 	log.SetFlags(log.Llongfile)
 
-	crontab := "f2|f2?3|f3?4|1|t4?5"
+	crontab := "f2|f2>3|f3>4|1|s4>5"
 	cron := NewCrontab(crontab)
 
 	i := 0
diff --git a/interval_base.go b/interval_base.go
index 2d65003..3512525 100644
--- a/interval_base.go
+++ b/interval_base.go
@@ -73,7 +73,7 @@ func parseIntervalString(crontab string) []interface{} {
 
 			switch FN[0] {
 			case 'f', 'F':
-				scharIndex := strings.Index(FN, "?")
+				scharIndex := strings.Index(FN, ">")
 				if scharIndex != -1 {
 
 					fc := FN[0:scharIndex]
@@ -89,8 +89,8 @@ func parseIntervalString(crontab string) []interface{} {
 					interval.PlanFail = append(interval.PlanFail, parseRandLR(fvalue))
 				}
 
-			case 't', 'T':
-				scharIndex := strings.Index(FN, "?")
+			case 's', 'S':
+				scharIndex := strings.Index(FN, ">")
 				if scharIndex != -1 {
 					tc := FN[0:scharIndex]
 					tlr := FN[scharIndex+1:]
@@ -106,8 +106,8 @@ func parseIntervalString(crontab string) []interface{} {
 				}
 
 			default:
-				FN = "t" + FN
-				scharIndex := strings.Index(FN, "?")
+				FN = "s" + FN
+				scharIndex := strings.Index(FN, ">")
 				if scharIndex != -1 {
 					tc := FN[0:scharIndex]
 					tlr := FN[scharIndex+1:]