diff --git a/dsmr_parser/parsers.py b/dsmr_parser/parsers.py
index 431b61c..cf91e2c 100644
--- a/dsmr_parser/parsers.py
+++ b/dsmr_parser/parsers.py
@@ -61,19 +61,22 @@ class TelegramParserV4(TelegramParser):
         :raises InvalidChecksumError:
         """
 
-        full_telegram = '\r\n'.join(line_values)
+        full_telegram = ''.join(line_values)
 
         # Extract the bytes that count towards the checksum.
-        contents = re.search(r'(\/.+\!)([0-9A-Z]{4})', full_telegram, re.DOTALL)
+        checksum_contents = re.search(r'\/.+\!', full_telegram, re.DOTALL)
 
-        if not contents:
+        # Extract the hexadecimal checksum value itself.
+        checksum_hex = re.search(r'((?<=\!)[0-9A-Z]{4}(?=\r\n))+', full_telegram)
+
+        if not checksum_contents or not checksum_hex:
             raise ParseError(
                 'Failed to perform CRC validation because the telegram is '
                 'incomplete. The checksum and/or content values are missing.'
             )
 
-        calculated_crc = CRC16().calculate(contents.group(1))
-        expected_crc = contents.group(2)
+        calculated_crc = CRC16().calculate(checksum_contents.group(0))
+        expected_crc = checksum_hex.group(0)
         expected_crc = int(expected_crc, base=16)
 
         if calculated_crc != expected_crc:
diff --git a/test/test_parse_v4_2.py b/test/test_parse_v4_2.py
index 897c5f3..58e757e 100644
--- a/test/test_parse_v4_2.py
+++ b/test/test_parse_v4_2.py
@@ -11,43 +11,43 @@ from dsmr_parser.objects import CosemObject, MBusObject
 from dsmr_parser.parsers import TelegramParser, TelegramParserV4
 
 TELEGRAM_V4_2 = [
-    '/KFM5KAIFA-METER',
-    '',
-    '1-3:0.2.8(42)',
-    '0-0:1.0.0(161113205757W)',
-    '0-0:96.1.1(3960221976967177082151037881335713)',
-    '1-0:1.8.1(001581.123*kWh)',
-    '1-0:1.8.2(001435.706*kWh)',
-    '1-0:2.8.1(000000.000*kWh)',
-    '1-0:2.8.2(000000.000*kWh)',
-    '0-0:96.14.0(0002)',
-    '1-0:1.7.0(02.027*kW)',
-    '1-0:2.7.0(00.000*kW)',
-    '0-0:96.7.21(00015)',
-    '0-0:96.7.9(00007)',
+    '/KFM5KAIFA-METER\r\n',
+    '\r\n',
+    '1-3:0.2.8(42)\r\n',
+    '0-0:1.0.0(161113205757W)\r\n',
+    '0-0:96.1.1(3960221976967177082151037881335713)\r\n',
+    '1-0:1.8.1(001581.123*kWh)\r\n',
+    '1-0:1.8.2(001435.706*kWh)\r\n',
+    '1-0:2.8.1(000000.000*kWh)\r\n',
+    '1-0:2.8.2(000000.000*kWh)\r\n',
+    '0-0:96.14.0(0002)\r\n',
+    '1-0:1.7.0(02.027*kW)\r\n',
+    '1-0:2.7.0(00.000*kW)\r\n',
+    '0-0:96.7.21(00015)\r\n',
+    '0-0:96.7.9(00007)\r\n',
     '1-0:99.97.0(3)(0-0:96.7.19)(000104180320W)(0000237126*s)(000101000001W)'
-    '(2147583646*s)(000102000003W)(2317482647*s)',
-    '1-0:32.32.0(00000)',
-    '1-0:52.32.0(00000)',
-    '1-0:72.32.0(00000)',
-    '1-0:32.36.0(00000)',
-    '1-0:52.36.0(00000)',
-    '1-0:72.36.0(00000)',
-    '0-0:96.13.1()',
-    '0-0:96.13.0()',
-    '1-0:31.7.0(000*A)',
-    '1-0:51.7.0(006*A)',
-    '1-0:71.7.0(002*A)',
-    '1-0:21.7.0(00.170*kW)',
-    '1-0:22.7.0(00.000*kW)',
-    '1-0:41.7.0(01.247*kW)',
-    '1-0:42.7.0(00.000*kW)',
-    '1-0:61.7.0(00.209*kW)',
-    '1-0:62.7.0(00.000*kW)',
-    '0-1:24.1.0(003)',
-    '0-1:96.1.0(4819243993373755377509728609491464)',
-    '0-1:24.2.1(161129200000W)(00981.443*m3)',
-    '!6796'
+    '(2147583646*s)(000102000003W)(2317482647*s)\r\n',
+    '1-0:32.32.0(00000)\r\n',
+    '1-0:52.32.0(00000)\r\n',
+    '1-0:72.32.0(00000)\r\n',
+    '1-0:32.36.0(00000)\r\n',
+    '1-0:52.36.0(00000)\r\n',
+    '1-0:72.36.0(00000)\r\n',
+    '0-0:96.13.1()\r\n',
+    '0-0:96.13.0()\r\n',
+    '1-0:31.7.0(000*A)\r\n',
+    '1-0:51.7.0(006*A)\r\n',
+    '1-0:71.7.0(002*A)\r\n',
+    '1-0:21.7.0(00.170*kW)\r\n',
+    '1-0:22.7.0(00.000*kW)\r\n',
+    '1-0:41.7.0(01.247*kW)\r\n',
+    '1-0:42.7.0(00.000*kW)\r\n',
+    '1-0:61.7.0(00.209*kW)\r\n',
+    '1-0:62.7.0(00.000*kW)\r\n',
+    '0-1:24.1.0(003)\r\n',
+    '0-1:96.1.0(4819243993373755377509728609491464)\r\n',
+    '0-1:24.2.1(161129200000W)(00981.443*m3)\r\n',
+    '!6796\r\n'
 ]