diff --git a/library/L3_Templates.ttcn b/library/L3_Templates.ttcn
index b39bb7a..3011919 100644
--- a/library/L3_Templates.ttcn
+++ b/library/L3_Templates.ttcn
@@ -35,6 +35,15 @@
 	CM_TYPE_LCS		('1011'B)
 }
 
+/* TS 24.008 10.5.3.4 Identity Type */
+type enumerated CmIdentityType {
+	CM_ID_TYPE_IMSI			('001'B),
+	CM_ID_TYPE_IMEI			('010'B),
+	CM_ID_TYPE_IMEISV		('011'B),
+	CM_ID_TYPE_TMSI			('100'B),
+	CM_ID_TYPE_PTMSI_RAI_PTMSI_SIG	('101'B)
+}
+
 template ML3_Cause_TLV ts_ML3_Cause(BIT7 cause, BIT4 loc := '0001'B, BIT2 std := '11'B) := {
 	elementIdentifier := '08'O,
 	lengthIndicator := 0, /* overwritten */
@@ -864,7 +873,7 @@
 	}
 }
 
-template PDU_ML3_NW_MS tr_ML3_MT_MM_ID_Req(template BIT3 id_type := ?) := {
+template PDU_ML3_NW_MS tr_ML3_MT_MM_ID_Req(template CmIdentityType id_type := ?) := {
 	discriminator := '0101'B,
 	tiOrSkip := {
 		skipIndicator := '0000'B
@@ -874,7 +883,7 @@
 			identityRequest := {
 				messageType := '011000'B,
 				nsd := '00'B,
-				identityType := id_type,
+				identityType := int2bit(enum2int(valueof(id_type)), 3),
 				spare1_5 := ?
 			}
 		}
diff --git a/msc/MSC_Tests.ttcn b/msc/MSC_Tests.ttcn
index f551513..6f9eecd 100644
--- a/msc/MSC_Tests.ttcn
+++ b/msc/MSC_Tests.ttcn
@@ -817,7 +817,7 @@
 	BSSAP.send(ts_BSSMAP_ClassmarkUpd(g_pars.cm2, g_pars.cm3));
 
 	/* Wait for + respond to ID REQ (IMSI) */
-	BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_MM_ID_Req('001'B)));
+	BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_MM_ID_Req(CM_ID_TYPE_IMSI)));
 	BSSAP.send(ts_PDU_DTAP_MO(ts_ML3_MO_MM_ID_Rsp_IMSI(overlong_imsi))); /* test for OS#2864 */
 	BSSAP.send(ts_PDU_DTAP_MO(ts_ML3_MO_MM_ID_Rsp_IMSI(g_pars.imsi)));