diff --git a/encoding/ascii.go b/encoding/ascii.go
index 7f4b083..2df3096 100644
--- a/encoding/ascii.go
+++ b/encoding/ascii.go
@@ -4,8 +4,9 @@ import "bytes"
 
 type ASCIICoder struct{}
 
-func (c *ASCIICoder) Encode(s string, buf *bytes.Buffer) error {
-	buf.WriteString(s)
+func (c *ASCIICoder) Encode(s *string, buf *bytes.Buffer) error {
+	// These should be ASCII but UTF8 is a superset of ASCII so hopefully this'll be fine
+	buf.WriteString(*s)
 	return nil
 }
 
diff --git a/encoding/ascii_test.go b/encoding/ascii_test.go
index bea47c9..631d29e 100644
--- a/encoding/ascii_test.go
+++ b/encoding/ascii_test.go
@@ -11,7 +11,7 @@ func TestASCIIEncodeSimpleASCIIString(t *testing.T) {
 	input := "Hello, World!"
 
 	expected := []byte{72, 101, 108, 108, 111, 44, 32, 87, 111, 114, 108, 100, 33}
-	err := coder.Encode(input, &buf)
+	err := coder.Encode(&input, &buf)
 
 	if err != nil {
 		t.Errorf("Expected no error, but got %v", err)
@@ -46,7 +46,7 @@ func TestASCIIEncodeEmptyString(t *testing.T) {
 	input := ""
 
 	expected := []byte{}
-	err := coder.Encode(input, &buf)
+	err := coder.Encode(&input, &buf)
 
 	if err != nil {
 		t.Errorf("Expected no error, but got %v", err)
diff --git a/encoding/coder.go b/encoding/coder.go
index 3a1ac50..76f30a3 100644
--- a/encoding/coder.go
+++ b/encoding/coder.go
@@ -3,6 +3,6 @@ package encoding
 import "bytes"
 
 type Coder interface {
-	Encode(s string, buf *bytes.Buffer) error
+	Encode(s *string, buf *bytes.Buffer) error
 	Decode(buf *bytes.Buffer) (string, error)
 }
\ No newline at end of file
diff --git a/encoding/gsm7.go b/encoding/gsm7.go
index 429443b..b2560c2 100644
--- a/encoding/gsm7.go
+++ b/encoding/gsm7.go
@@ -11,15 +11,15 @@ type GSM7Coder struct{}
 // Otherwise Encode will allocate memory as it sees fit
 // Which is fine but not optimal
 // Preallocate the buffer with the size of EncodesInto bytes
-func (c *GSM7Coder) Encode(s string, buf *bytes.Buffer) error {
+func (c *GSM7Coder) Encode(s *string, buf *bytes.Buffer) error {
 	// utf8 := *(*[]byte)(unsafe.Pointer(&s))
-	utf8 := []byte(s)
+	utf8 := []byte(*s)
 	var (
 		offset      int  = 1
 		bitshift    byte = 0
 		leap, shift bool
 	)
-	encodedSize := GSM7EncodesInto(&s)
+	encodedSize := GSM7EncodesInto(s)
 	cap := buf.Cap()
 	if cap < encodedSize {
 		buf.Grow(encodedSize - cap)
diff --git a/encoding/gsm7_test.go b/encoding/gsm7_test.go
index e2818c2..47f9053 100644
--- a/encoding/gsm7_test.go
+++ b/encoding/gsm7_test.go
@@ -22,7 +22,7 @@ func TestGSM7EncodeSimpleASCIIString(t *testing.T) {
 	input := short8nString
 
 	expected := short8nStringEncodedBytes
-	err := coder.Encode(input, &buf)
+	err := coder.Encode(&input, &buf)
 
 	if err != nil {
 		t.Errorf("Expected no error, but got %v", err)
@@ -39,7 +39,7 @@ func TestGSM7EncodeComplexASCIIString(t *testing.T) {
 	input := longNot8nString
 
 	expected := longNot8nStringEncodedBytes
-	err := coder.Encode(input, &buf)
+	err := coder.Encode(&input, &buf)
 
 	if err != nil {
 		t.Errorf("Expected no error, but got %v", err)
@@ -56,7 +56,7 @@ func TestGSM7EncodeComplex8nASCIIString(t *testing.T) {
 	input := "Ducks are fucking great, they quacks, O quackers, what the fuck."
 
 	expected := long8nStringEncodedBytes
-	err := coder.Encode(input, &buf)
+	err := coder.Encode(&input, &buf)
 
 	if err != nil {
 		t.Errorf("Expected no error, but got %v", err)
@@ -74,7 +74,7 @@ func TestGSM7EncodeDoesNotAllocateMoreThanNecessary(t *testing.T) {
 	buf.Reset()
 
 	expected := buf.Cap()
-	err := coder.Encode(input, buf)
+	err := coder.Encode(&input, buf)
 	actual := buf.Cap()
 
 	if err != nil {
@@ -93,7 +93,7 @@ func TestGSM7EncodeDoesAllocateWhenNecessary(t *testing.T) {
 	buf.Reset()
 
 	original := buf.Cap()
-	err := coder.Encode(input, &buf)
+	err := coder.Encode(&input, &buf)
 	modified := buf.Cap()
 
 	if err != nil {
@@ -111,7 +111,7 @@ func TestGSM7EncodeEmptyString(t *testing.T) {
 	input := ""
 
 	expected := []byte{}
-	err := coder.Encode(input, &buf)
+	err := coder.Encode(&input, &buf)
 
 	if err != nil {
 		t.Errorf("Expected no error, but got %v", err)
@@ -330,7 +330,7 @@ func BenchmarkGSM7EncodeSimpleASCIIString(b *testing.B) {
 	b.ResetTimer()
 
 	for i := 0; i < b.N; i++ {
-		coder.Encode(input, &buf)
+		coder.Encode(&input, &buf)
 	}
 }
 
@@ -341,7 +341,7 @@ func BenchmarkGSM7EncodeComplexASCIIString(b *testing.B) {
 	b.ResetTimer()
 
 	for i := 0; i < b.N; i++ {
-		coder.Encode(input, &buf)
+		coder.Encode(&input, &buf)
 	}
 }
 
@@ -352,7 +352,7 @@ func BenchmarkGSM7EncodeComplex8nASCIIString(b *testing.B) {
 	b.ResetTimer()
 
 	for i := 0; i < b.N; i++ {
-		coder.Encode(input, &buf)
+		coder.Encode(&input, &buf)
 	}
 }
 
@@ -364,6 +364,6 @@ func BenchmarkGSM7EncodeComplex8nASCIIStringPrealloc(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		buf := bytes.NewBuffer(make([]byte, GSM7EncodesInto(&input)))
 		buf.Reset()
-		coder.Encode(input, buf)
+		coder.Encode(&input, buf)
 	}
 }