diff --git a/info/code.go b/info/code.go
index 4163914..cf236b3 100644
--- a/info/code.go
+++ b/info/code.go
@@ -467,28 +467,28 @@ var errCauseZero = errors.New("part5: cause of transmission <0> is not used")
 // “Additional cause of transmission”.
 const (
 	_        Cause = iota // 0: not defined
-	Percyc                // periodic, cyclic
+	Cyclic                // periodic, cyclic
 	Back                  // background scan
 	Spont                 // spontaneous
 	Init                  // initialized
 	Req                   // request or requested
 	Act                   // activation
-	Actcon                // activation confirmation
+	ActCon                // activation confirmation
 	Deact                 // deactivation
-	Deactcon              // deactivation confirmation
+	DeactCon              // deactivation confirmation
 
-	Actterm // activation termination
-	Retrem  // return information caused by a remote command
-	Retloc  // return information caused by a local command
+	ActTerm // activation termination
+	RetRem  // return information caused by a remote command
+	RetLoc  // return information caused by a local command
 	File    // file transfer
 	Auth    // authentication
-	Seskey  // maintenance of authentication session key
-	Usrkey  // maintenance of user role and update key
+	SesKey  // maintenance of authentication session key
+	UsrKey  // maintenance of user role and update key
 	_       // 17: reserved for further compatible definitions
 	_       // 18: reserved for further compatible definitions
 	_       // 19: reserved for further compatible definitions
 
-	Inrogen // interrogated by station interrogation
+	InroGen // interrogated by station interrogation
 	Inro1   // interrogated by group 1 interrogation
 	Inro2   // interrogated by group 2 interrogation
 	Inro3   // interrogated by group 3 interrogation
@@ -506,12 +506,12 @@ const (
 	Inro14   // interrogated by group 14 interrogation
 	Inro15   // interrogated by group 15 interrogation
 	Inro16   // interrogated by group 16 interrogation
-	Reqcogen // requested by general counter request
-	Reqco1   // requested by group 1 counter request
-	Reqco2   // requested by group 2 counter request
-	Reqco3   // requested by group 3 counter request
+	ReqCoGen // requested by general counter request
+	ReqCo1   // requested by group 1 counter request
+	ReqCo2   // requested by group 2 counter request
+	ReqCo3   // requested by group 3 counter request
 
-	Reqco4   // requested by group 4 counter request
+	ReqCo4   // requested by group 4 counter request
 	_        // 41: reserved for further compatible definitions
 	_        // 42: reserved for further compatible definitions
 	UnkType  // unknown type identification
@@ -561,7 +561,7 @@ func (c Cause) String() string {
 
 var causeLabels = [64]string{
 	"notdef",
-	"per/cyc",
+	"cyclic", // conform section 5 instead of "per/cyc" introduced by companion standard 101
 	"back",
 	"spont",
 	"init",
diff --git a/info/packet_test.go b/info/packet_test.go
index c9eac36..60b20d0 100644
--- a/info/packet_test.go
+++ b/info/packet_test.go
@@ -16,12 +16,12 @@ var goldenDataUnits = []struct {
 		DataUnit[OrigAddr8, ComAddr16, ObjAddr16]{
 			Type:  M_SP_NA_1,
 			Enc:   1,
-			Cause: Percyc,
+			Cause: Cyclic,
 			Orig:  Wide.MustOrigAddrN(7),
 			Addr:  Wide.MustComAddrN(1001),
 			Info:  []byte{1, 2, 3},
 		},
-		"M_SP_NA_1 per/cyc 7 1001: 0x03@513 .",
+		"M_SP_NA_1 cyclic 7 1001: 0x03@513 .",
 	}, {
 		DataUnit[OrigAddr8, ComAddr16, ObjAddr16]{
 			Type:  M_DP_NA_1,
@@ -38,11 +38,11 @@ var goldenDataUnits = []struct {
 		DataUnit[OrigAddr8, ComAddr16, ObjAddr16]{
 			Type:  M_SP_NA_1,
 			Enc:   0,
-			Cause: Percyc,
+			Cause: Cyclic,
 			Addr:  Wide.MustComAddrN(404),
 			Info:  []byte{},
 		},
-		"M_SP_NA_1 per/cyc 0 404: .",
+		"M_SP_NA_1 cyclic 0 404: .",
 	}, {
 		DataUnit[OrigAddr8, ComAddr16, ObjAddr16]{
 			Type:  M_DP_NA_1,
diff --git a/part5.go b/part5.go
index 51818cd..7127e5a 100644
--- a/part5.go
+++ b/part5.go
@@ -43,7 +43,7 @@ func isCommand(t info.TypeID) bool {
 	return t-45 < 25
 }
 
-// Response alternatives to info.Actcon are propagated as errors for simplicity.
+// Response alternatives to info.ActCon are propagated as errors for simplicity.
 var (
 	// A negative confirm denies without justification.
 	ErrConNeg = errors.New("part5: command not activated [actcon, P/N := <1>]")
@@ -77,18 +77,18 @@ func ConOf[Orig info.OrigAddr, Com info.ComAddr, Obj info.ObjAddr](in, req info.
 
 	// match cause of transmission, or not
 	switch in.Cause &^ info.TestFlag {
-	case info.Actcon:
+	case info.ActCon:
 		if req.Cause&^info.TestFlag == info.Act {
 			return nil // OK
 		}
-	case info.Deactcon:
+	case info.DeactCon:
 		if req.Cause&^info.TestFlag == info.Deact {
 			return nil // OK
 		}
 
-	case info.Actcon | info.NegFlag:
+	case info.ActCon | info.NegFlag:
 		return ErrConNeg
-	case info.Actterm:
+	case info.ActTerm:
 		return ErrTerm
 
 	// “ASDUs in the control direction with undefined values in the data