diff --git a/pySim/cards.py b/pySim/cards.py
index 61d2624c..8b51787a 100644
--- a/pySim/cards.py
+++ b/pySim/cards.py
@@ -631,7 +631,7 @@ class FakeMagicSim(Card):
 		# Set first entry
 		entry = (
 			'81' +					#  1b  Status: Valid & Active
-			rpad(b2h(p['name'][0:14]), 28) +	# 14b  Entry Name
+			rpad(s2h(p['name'][0:14]), 28) +	# 14b  Entry Name
 			enc_iccid(p['iccid']) +			# 10b  ICCID
 			enc_imsi(p['imsi']) +			#  9b  IMSI_len + id_type(9) + IMSI
 			p['ki'] +				# 16b  Ki
diff --git a/pySim/utils.py b/pySim/utils.py
index bfa147b4..5320b597 100644
--- a/pySim/utils.py
+++ b/pySim/utils.py
@@ -22,10 +22,12 @@
 
 
 def h2b(s):
-	return ''.join([chr((int(x,16)<<4)+int(y,16)) for x,y in zip(s[0::2], s[1::2])])
+	"""convert from a string of hex nibbles to a sequence of bytes"""
+	return bytearray.fromhex(s)
 
-def b2h(s):
-	return ''.join(['%02x'%ord(x) for x in s])
+def b2h(b):
+	"""convert from a sequence of bytes to a string of hex nibbles"""
+	return ''.join(['%02x'%(x) for x in b])
 
 def h2i(s):
 	return [(int(x,16)<<4)+int(y,16) for x,y in zip(s[0::2], s[1::2])]
@@ -38,7 +40,9 @@ def h2s(s):
 						      if int(x + y, 16) != 0xff])
 
 def s2h(s):
-	return b2h(s)
+	b = bytearray()
+	b.extend(map(ord, s))
+	return b2h(b)
 
 # List of bytes to string
 def i2s(s):
@@ -334,7 +338,7 @@ def dec_msisdn(ef_msisdn):
 	msisdn_lhv = ef_msisdn[xlen:]
 
 	# Parse the length (in bytes) of the BCD encoded number
-	bcd_len = ord(msisdn_lhv[0])
+	bcd_len = msisdn_lhv[0]
 	# BCD length = length of dial num (max. 10 bytes) + 1 byte ToN and NPI
 	if bcd_len == 0xff:
 		return None
@@ -342,8 +346,8 @@ def dec_msisdn(ef_msisdn):
 		raise ValueError("Length of MSISDN (%d bytes) is out of range" % bcd_len)
 
 	# Parse ToN / NPI
-	ton = (ord(msisdn_lhv[1]) >> 4) & 0x07
-	npi = ord(msisdn_lhv[1]) & 0x0f
+	ton = (msisdn_lhv[1] >> 4) & 0x07
+	npi = msisdn_lhv[1] & 0x0f
 	bcd_len -= 1
 
 	# No MSISDN?