diff --git a/apier/v1/cdre.go b/apier/v1/cdre.go
index 63e5fe101..2591c0503 100644
--- a/apier/v1/cdre.go
+++ b/apier/v1/cdre.go
@@ -29,6 +29,7 @@ import (
 	"strconv"
 	"strings"
 	"time"
+	"unicode/utf8"
 
 	"github.com/cgrates/cgrates/cdre"
 	"github.com/cgrates/cgrates/config"
@@ -117,8 +118,11 @@ func (self *ApierV1) ExportCdrsToFile(attr utils.AttrExpFileCdrs, reply *utils.E
 		return fmt.Errorf("%s:%s", utils.ERR_MANDATORY_IE_MISSING, "CdrFormat")
 	}
 	fieldSep := exportTemplate.FieldSeparator
-	if attr.FieldSeparator != nil {
-		fieldSep = *attr.FieldSeparator
+	if attr.FieldSeparator != nil && len(*attr.FieldSeparator) != 0 {
+		fieldSep, _ = utf8.DecodeRuneInString(*attr.FieldSeparator)
+		if fieldSep == utf8.RuneError {
+			return fmt.Errorf("%s:FieldSeparator:%s", utils.ERR_SERVER_ERROR, "Invalid")
+		}
 	}
 	exportDir := exportTemplate.ExportDir
 	if attr.ExportDir != nil && len(*attr.ExportDir) != 0 {
diff --git a/utils/apitpdata.go b/utils/apitpdata.go
index d58f80324..2c7eec007 100644
--- a/utils/apitpdata.go
+++ b/utils/apitpdata.go
@@ -517,7 +517,7 @@ type CachedItemAge struct {
 
 type AttrExpFileCdrs struct {
 	CdrFormat               *string  // Cdr output file format <utils.CdreCdrFormats>
-	FieldSeparator          *rune    // Separator used between fields
+	FieldSeparator          *string  // Separator used between fields
 	ExportId                *string  // Optional exportid
 	ExportDir               *string  // If provided it overwrites the configured export directory
 	ExportFileName          *string  // If provided the output filename will be set to this
diff --git a/utils/storedcdr_test.go b/utils/storedcdr_test.go
index 9bf45c31a..d8f022747 100644
--- a/utils/storedcdr_test.go
+++ b/utils/storedcdr_test.go
@@ -232,6 +232,14 @@ func TestFormatUsage(t *testing.T) {
 	if cdr.FormatUsage("default") != "1640113" {
 		t.Error("Wrong usage format: ", cdr.FormatUsage("default"))
 	}
+	cdr = StoredCdr{Usage: time.Duration(2) * time.Millisecond}
+	if cdr.FormatUsage("default") != "0.002" {
+		t.Error("Wrong usage format: ", cdr.FormatUsage("default"))
+	}
+	cdr = StoredCdr{Usage: time.Duration(1002) * time.Millisecond}
+	if cdr.FormatUsage("default") != "1.002" {
+		t.Error("Wrong usage format: ", cdr.FormatUsage("default"))
+	}
 }
 
 func TestStoredCdrAsHttpForm(t *testing.T) {
diff --git a/utils/utils_test.go b/utils/utils_test.go
index c223cefe6..b6e436809 100644
--- a/utils/utils_test.go
+++ b/utils/utils_test.go
@@ -389,6 +389,20 @@ func TestParseDurationWithSecs(t *testing.T) {
 	} else if parsed != durExpected {
 		t.Error("Parsed different than expected")
 	}
+	durStr = "0.002"
+	durExpected = time.Duration(2) * time.Millisecond
+	if parsed, err := ParseDurationWithSecs(durStr); err != nil {
+		t.Error(err)
+	} else if parsed != durExpected {
+		t.Error("Parsed different than expected")
+	}
+	durStr = "1.002"
+	durExpected = time.Duration(1002) * time.Millisecond
+	if parsed, err := ParseDurationWithSecs(durStr); err != nil {
+		t.Error(err)
+	} else if parsed != durExpected {
+		t.Error("Parsed different than expected")
+	}
 }
 
 func TestMinDuration(t *testing.T) {