diff --git a/src/ChecksumConverter.cc b/src/ChecksumConverter.cc
index 8b50e48..8e718e0 100644
--- a/src/ChecksumConverter.cc
+++ b/src/ChecksumConverter.cc
@@ -2,7 +2,7 @@
 * StreamDevice Support                                         *
 *                                                              *
 * (C) 1999 Dirk Zimoch (zimoch@delta.uni-dortmund.de)          *
-* (C) 2006 Dirk Zimoch (dirk.zimoch@psi.ch)                    *
+* (C) 2006-2018 Dirk Zimoch (dirk.zimoch@psi.ch)               *
 *                                                              *
 * This is the checksum pseudo-converter of StreamDevice.       *
 * Please refer to the HTML files in ../doc/ for a detailed     *
@@ -457,6 +457,36 @@ static unsigned int hexsum(const unsigned char* data, size_t len, unsigned int s
     return sum;
 }
 
+// Special TRIUMF version for the CPI RF Amplifier
+static unsigned int CPI(const unsigned char * data, size_t len, unsigned int init)
+{
+    unsigned long  i = len * 32;
+    while (len--)
+    {
+        init += *data++;
+    } 
+    init -= i;
+    init %= 95;
+    init += 32;
+    return init;
+}
+
+// Leybold Graphix uses a strange sum (= notsum + fix):
+// "CRC = 255 - [(Byte sum of all preceding characters) mod 256]
+//  If this value is lower than 32 (control character of the ASCII code),
+//  then 32 must be added."
+
+static unsigned int leybold(const unsigned char* data, size_t len, unsigned int sum)
+{
+    while (len--)
+    {
+        sum += *data++;
+    }
+    sum = ~sum;
+    if (sum < 32) sum+=32;
+    return sum;
+}
+
 struct checksum
 {
     const char* name;
@@ -491,7 +521,9 @@ static checksum checksumMap[] =
     {"crc32r",  crc_0x04C11DB7_r, 0xFFFFFFFF, 0xFFFFFFFF, 4}, // 0xCBF43926
     {"jamcrc",  crc_0x04C11DB7_r, 0xFFFFFFFF, 0x00000000, 4}, // 0x340BC6D9
     {"adler32", adler32,          0x00000001, 0x00000000, 4}, // 0x091E01DE
-    {"hexsum8", hexsum,           0x00,       0x00,       1}  // 0x2D
+    {"hexsum8", hexsum,           0x00,       0x00,       1}, // 0x2D
+    {"cpi",     CPI,              0x00,       0x00,       1}, // 0x7E
+    {"leybold", leybold,          0x00,       0x00,       1}, // 0x22
 };
 
 static unsigned int mask[5] = {0, 0xFF, 0xFFFF, 0xFFFFFF, 0xFFFFFFFF};
diff --git a/streamApp/checksums.cmd b/streamApp/checksums.cmd
new file mode 100755
index 0000000..2c3ed77
--- /dev/null
+++ b/streamApp/checksums.cmd
@@ -0,0 +1,15 @@
+#!/bin/sh
+exec O.$EPICS_HOST_ARCH/streamApp $0
+dbLoadDatabase "O.Common/streamApp.dbd"
+streamApp_registerRecordDeviceDriver
+
+drvAsynIPPortConfigure "terminal", "localhost:40000"
+
+dbLoadRecords checksums.db
+
+#log debug output to file
+#streamSetLogfile StreamDebug.log
+var streamError 1
+
+iocInit
+#var streamDebug 1
diff --git a/streamApp/checksums.db b/streamApp/checksums.db
new file mode 100644
index 0000000..9cbfa95
--- /dev/null
+++ b/streamApp/checksums.db
@@ -0,0 +1,7 @@
+record (stringout, "DZ:checksums")
+{
+    field (DTYP, "stream")
+    field (OUT,  "@checksums.proto write terminal")
+    field (VAL,  "123456789")
+    field (PINI, "YES")
+}
diff --git a/streamApp/checksums.proto b/streamApp/checksums.proto
new file mode 100644
index 0000000..7897d0d
--- /dev/null
+++ b/streamApp/checksums.proto
@@ -0,0 +1,37 @@
+Terminator = NL;
+
+# Output string, checksum name and checksum value
+# Format checksums as ascii hex (%0 flag)
+# Ignore the 12 chars (.12) between the sting (%s) and the checksum (%<...)
+
+write {
+    out "%s  sum       %0.12<sum>";
+    out "%s  sum8      %0.12<sum8>";
+    out "%s  ~sum      %0.12<~sum>";
+    out "%s  notsum    %0.12<notsum>";
+    out "%s  -sum      %0.12<-sum>";
+    out "%s  negsum    %0.12<negsum>";
+    out "%s  sum16     %0.12<sum16>";
+    out "%s  sum32     %0.12<sum32>";
+    out "%s  xor       %0.12<xor>";
+    out "%s  xor8      %0.12<xor8>";
+    out "%s  xor7      %0.12<xor7>";
+    out "%s  crc8      %0.12<crc8>";
+    out "%s  ccitt8    %0.12<ccitt8>";
+    out "%s  crc16     %0.12<crc16>";
+    out "%s  crc16r    %0.12<crc16r>";
+    out "%s  modbus    %0.12<modbus>";
+    out "%s  ccitt16   %0.12<ccitt16>";
+    out "%s  ccitt16a  %0.12<ccitt16a>";
+    out "%s  ccitt16x  %0.12<ccitt16x>";
+    out "%s  crc16c    %0.12<crc16c>";
+    out "%s  xmodem    %0.12<xmodem>";
+    out "%s  crc32     %0.12<crc32>";
+    out "%s  crc32r    %0.12<crc32r>";
+    out "%s  jamcrc    %0.12<jamcrc>";
+    out "%s  adler32   %0.12<adler32>";
+    out "%s  adler32b  %0.12<adler32b>";
+    out "%s  hexsum8   %0.12<hexsum8>";
+    out "%s  cpi       %0.12<cpi>";
+    out "%s  leybold   %0.12<leybold>";
+}
diff --git a/streamApp/test.db b/streamApp/test.db
index 283ca82..3423554 100644
--- a/streamApp/test.db
+++ b/streamApp/test.db
@@ -20,6 +20,11 @@ record (stringout, "$(P):request")
 record (stringin, "$(P):reply")
 {
 }
+record (stringout, "$(P):checksum")
+{
+    field (DTYP, "stream")
+    field (OUT,  "@test.proto checksum($(CHKSUM=sum)) terminal")
+}
 record (stringin, "$(P):spy")
 {
     field (DTYP, "stream")
@@ -134,3 +139,4 @@ record (waveform, "$(P):spybin")
     field (NELM, "2000")
     field (SCAN, "I/O Intr")
 }
+
diff --git a/streamApp/test.proto b/streamApp/test.proto
index 4e0964f..9cae40d 100644
--- a/streamApp/test.proto
+++ b/streamApp/test.proto
@@ -23,3 +23,6 @@ spybin {
     extraInput=ignore;
     in "%r";
 }
+checksum {
+    out "%s %0.1<\$1>";
+}