diff --git a/README.md b/README.md
index ea58f49..7d409eb 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,7 @@ RTU version also features:
     - pkg-config
   - Prereq: Download and install libmodbus
   - Run `autogen.sh`
+  - `./configure --enable-zabbix-3` or `./configure --enable-zabbix-2`
   - `make`
   - `make install`  
   
@@ -34,7 +35,7 @@ RTU version also features:
 Download from  https://share.zabbix.com/dir-libraries/zabbix-loadable-modules/modbus-loadable-module
   - `tar zxvpf libzbxmodbus-0.1.tar.gz`
   - `cd libzbxmodbus-0.1`
-  - `./configure`
+  - `./configure --enable-zabbix-3` or `./configure --enable-zabbix-2`
   - `make`
   - `make install`
 
@@ -86,7 +87,8 @@ and some optional params can be provided as well:
 * **datatype(optional):**  
     provide datatype as single char:  
       b - for MODBUS_BIT  
-      i - for MODBUS_INTEGER  
+      i - for MODBUS_INTEGER (unsigned)  
+      s - for MODBUS_SIGNED_INT (NOTE: in Zabbix use 'Type of information' Numeric(float) )  
       l - for MODBUS_LONG  
       f - for MODBUS_FLOAT  
     otherwise, defaults will be used:  
diff --git a/configure.ac b/configure.ac
index 58a1f81..2f36352 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-AC_INIT([libzbxmodbus], [0.2])
+AC_INIT([libzbxmodbus], [0.3])
 AM_INIT_AUTOMAKE([foreign -Wall -Werror])
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_SRCDIR([src/modbus.c])
@@ -22,6 +22,44 @@ PKG_CHECK_MODULES([LIBMODBUS], [libmodbus >= 3.1.1], [],
     libmodbus from http://libmodbus.org/
     ------------------------------------------])
 ])
+
+#Zabbix 2.4 / Zabbix 3.0 chooser
+AC_ARG_ENABLE([zabbix-2],
+[  --enable-zabbix-2    Build with Zabbix 2.4 headers],
+[case "${enableval}" in
+  yes) zabbix_2=true ;;
+  no)  zabbix_2=false ;;
+  *) AC_MSG_ERROR([bad value ${enableval} for --enable-zabbix-2]) ;;
+esac],[zabbix_2=false])
+AM_CONDITIONAL([ZABBIX_2], [test x$zabbix_2 = xtrue])
+
+AC_ARG_ENABLE([zabbix-3],
+[  --enable-zabbix-3    Build with Zabbix 3.0 headers],
+[case "${enableval}" in
+  yes) zabbix_3=true ;;
+  no)  zabbix_3=false ;;
+  *) AC_MSG_ERROR([bad value ${enableval} for --enable-zabbix-3]) ;;
+esac],[zabbix_3=false])
+AM_CONDITIONAL([ZABBIX_3], [test x$zabbix_3 = xtrue])
+
+
+if [test "x${zabbix_2}" = xfalse && test "x${zabbix_3}" = xfalse] ; then
+AC_MSG_ERROR([
+------------------------------------------
+Please specify the version of Zabbix module will be used with: by providing either
+--enable-zabbix-2 or --enable-zabbix-3 key but not both.
+------------------------------------------])
+fi
+
+if [test "x${zabbix_2}" = xtrue && test "x${zabbix_3}" = xtrue] ; then
+AC_MSG_ERROR([
+------------------------------------------
+Please specify the version of Zabbix module will be used with: by providing either
+--enable-zabbix-2 or --enable-zabbix-3 key but not both.
+------------------------------------------])
+fi
+
+
 LT_INIT
 AC_DISABLE_STATIC([yes])
 AC_PROG_CC
diff --git a/include/module.h b/include/zabbix-2.4/module.h
similarity index 100%
rename from include/module.h
rename to include/zabbix-2.4/module.h
diff --git a/include/sysinc.h b/include/zabbix-2.4/sysinc.h
similarity index 100%
rename from include/sysinc.h
rename to include/zabbix-2.4/sysinc.h
diff --git a/include/zbxtypes.h b/include/zabbix-2.4/zbxtypes.h
similarity index 100%
rename from include/zbxtypes.h
rename to include/zabbix-2.4/zbxtypes.h
diff --git a/include/zabbix-3.0/module.h b/include/zabbix-3.0/module.h
new file mode 100644
index 0000000..f0c5ecd
--- /dev/null
+++ b/include/zabbix-3.0/module.h
@@ -0,0 +1,138 @@
+/*
+** Zabbix
+** Copyright (C) 2001-2016 Zabbix SIA
+**
+** This program is free software; you can redistribute it and/or modify
+** it under the terms of the GNU General Public License as published by
+** the Free Software Foundation; either version 2 of the License, or
+** (at your option) any later version.
+**
+** This program is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+** GNU General Public License for more details.
+**
+** You should have received a copy of the GNU General Public License
+** along with this program; if not, write to the Free Software
+** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+**/
+
+#ifndef ZABBIX_MODULE_H
+#define ZABBIX_MODULE_H
+
+#include "zbxtypes.h"
+
+#define ZBX_MODULE_OK	0
+#define ZBX_MODULE_FAIL	-1
+
+#define ZBX_MODULE_API_VERSION_ONE	1
+
+#define get_rkey(request)		(request)->key
+#define get_rparams_num(request)	(request)->nparam
+#define get_rparam(request, num)	((request)->nparam > num ? (request)->params[num] : NULL)
+
+/* flags for command */
+#define CF_HAVEPARAMS		0x01	/* item accepts either optional or mandatory parameters */
+#define CF_MODULE		0x02	/* item is defined in a loadable module */
+#define CF_USERPARAMETER	0x04	/* item is defined as user parameter */
+
+typedef struct
+{
+	char		*key;
+	unsigned	flags;
+	int		(*function)();
+	char		*test_param;	/* item test parameters; user parameter items keep command here */
+}
+ZBX_METRIC;
+
+/* agent request structure */
+typedef struct
+{
+	char		*key;
+	int		nparam;
+	char		**params;
+	zbx_uint64_t	lastlogsize;
+	int		mtime;
+}
+AGENT_REQUEST;
+
+typedef struct
+{
+	char		*value;
+	char		*source;
+	int		timestamp;
+	int		severity;
+	int		logeventid;
+}
+zbx_log_t;
+
+/* agent result types */
+#define AR_UINT64	0x01
+#define AR_DOUBLE	0x02
+#define AR_STRING	0x04
+#define AR_TEXT		0x08
+#define AR_LOG		0x10
+#define AR_MESSAGE	0x20
+#define AR_META		0x40
+
+/* agent return structure */
+typedef struct
+{
+	zbx_uint64_t	lastlogsize;	/* meta information */
+	zbx_uint64_t	ui64;
+	double		dbl;
+	char		*str;
+	char		*text;
+	char		*msg;		/* possible error message */
+	zbx_log_t	*log;
+	int	 	type;		/* flags: see AR_* above */
+	int		mtime;		/* meta information */
+}
+AGENT_RESULT;
+
+/* SET RESULT */
+
+#define SET_UI64_RESULT(res, val)		\
+(						\
+	(res)->type |= AR_UINT64,		\
+	(res)->ui64 = (zbx_uint64_t)(val)	\
+)
+
+#define SET_DBL_RESULT(res, val)		\
+(						\
+	(res)->type |= AR_DOUBLE,		\
+	(res)->dbl = (double)(val)		\
+)
+
+/* NOTE: always allocate new memory for val! DON'T USE STATIC OR STACK MEMORY!!! */
+#define SET_STR_RESULT(res, val)		\
+(						\
+	(res)->type |= AR_STRING,		\
+	(res)->str = (char *)(val)		\
+)
+
+/* NOTE: always allocate new memory for val! DON'T USE STATIC OR STACK MEMORY!!! */
+#define SET_TEXT_RESULT(res, val)		\
+(						\
+	(res)->type |= AR_TEXT,			\
+	(res)->text = (char *)(val)		\
+)
+
+/* NOTE: always allocate new memory for val! DON'T USE STATIC OR STACK MEMORY!!! */
+#define SET_LOG_RESULT(res, val)		\
+(						\
+	(res)->type |= AR_LOG,			\
+	(res)->log = (zbx_log_t *)(val)		\
+)
+
+/* NOTE: always allocate new memory for val! DON'T USE STATIC OR STACK MEMORY!!! */
+#define SET_MSG_RESULT(res, val)		\
+(						\
+	(res)->type |= AR_MESSAGE,		\
+	(res)->msg = (char *)(val)		\
+)
+
+#define SYSINFO_RET_OK		0
+#define SYSINFO_RET_FAIL	1
+
+#endif
diff --git a/include/zabbix-3.0/sysinc.h b/include/zabbix-3.0/sysinc.h
new file mode 100644
index 0000000..4891be3
--- /dev/null
+++ b/include/zabbix-3.0/sysinc.h
@@ -0,0 +1,438 @@
+/*
+** Zabbix
+** Copyright (C) 2001-2016 Zabbix SIA
+**
+** This program is free software; you can redistribute it and/or modify
+** it under the terms of the GNU General Public License as published by
+** the Free Software Foundation; either version 2 of the License, or
+** (at your option) any later version.
+**
+** This program is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+** GNU General Public License for more details.
+**
+** You should have received a copy of the GNU General Public License
+** along with this program; if not, write to the Free Software
+** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+**/
+
+#ifndef ZABBIX_SYSINC_H
+#define ZABBIX_SYSINC_H
+
+#include "config.h"
+
+#ifdef HAVE_STDIO_H
+#	include <stdio.h>
+#endif
+
+#ifdef HAVE_STDLIB_H
+#	include <stdlib.h>
+#endif
+
+#ifdef HAVE_ASSERT_H
+#	include <assert.h>
+#endif
+
+#ifdef HAVE_ERRNO_H
+#	include <errno.h>
+#endif
+
+#ifdef HAVE_WINSOCK2_H
+#	include <winsock2.h>
+#endif
+
+#ifdef HAVE_WS2TCPIP_H
+#	include <ws2tcpip.h>
+#endif
+
+#ifdef HAVE_WSPIAPI_H
+#	include "Wspiapi.h"
+#endif
+
+#ifdef HAVE_IPHLPAPI_H
+#	include <Iphlpapi.h>
+#endif
+
+#ifdef HAVE_NETIOAPI_H
+#	include <Netioapi.h>
+#endif
+
+#ifdef HAVE_WINDOWS_H
+/* to speed build process and reduce size of the Win32 header files */
+#	define WIN32_LEAN_AND_MEAN	1
+#	include <windows.h>
+#endif
+
+#ifdef HAVE_PROCESS_H
+#	include <process.h>
+#endif
+
+#ifdef HAVE_CONIO_H
+#	include <conio.h>
+#endif
+
+#ifdef HAVE_PDH_H
+#	include <pdh.h>
+#	ifndef PDH_MAX_COUNTER_NAME
+#		define PDH_MAX_COUNTER_NAME	1024	/* maximum counter name length */
+#	endif
+#	ifndef PDH_MAX_COUNTER_PATH
+#		define PDH_MAX_COUNTER_PATH	2048	/* maximum full counter path length */
+#	endif
+#endif
+
+#ifdef HAVE_PDHMSG_H
+#	include <pdhmsg.h>
+#endif
+
+#ifdef HAVE_PSAPI_H
+#	include <psapi.h>
+#endif
+
+#ifdef HAVE_STDARG_H
+#	include <stdarg.h>
+#endif
+
+#ifdef HAVE_CTYPE_H
+#	include <ctype.h>
+#endif
+
+#ifdef HAVE_GRP_H
+#	include <grp.h>
+#endif
+
+#ifdef HAVE_SYS_TYPES_H
+#	include <sys/types.h>
+#endif
+
+#ifdef HAVE_SYS_SYSTEMCFG_H
+#	include <sys/systemcfg.h>
+#endif
+
+#ifdef HAVE_INTTYPES_H
+#	include <inttypes.h>
+#endif
+
+#ifdef HAVE_STRING_H
+#	include <string.h>
+#endif
+
+#ifdef HAVE_STRINGS_H
+#	include <strings.h>
+#endif
+
+#ifdef HAVE_SYS_TIME_H
+#	include <sys/time.h>
+#endif
+
+#ifdef HAVE_SYS_TIMES_H
+#	include <sys/times.h>
+#endif
+
+#ifdef HAVE_LINUX_KERNEL_H
+#	include <linux/kernel.h>
+#endif
+
+#ifdef HAVE_ARPA_NAMESER_H
+#	ifdef MAC_OS_X
+#		define BIND_8_COMPAT 1
+#	endif
+#	include <arpa/nameser.h>
+#endif
+
+#ifdef HAVE_DIRENT_H
+#	include <dirent.h>
+#endif
+
+#ifdef HAVE_SYS_DKSTAT_H
+#	include <sys/dkstat.h>
+#endif
+
+#ifdef HAVE_DEVSTAT_H
+#	include <devstat.h>
+#endif
+
+#ifdef HAVE_FCNTL_H
+#	include <fcntl.h>
+#endif
+
+#ifdef HAVE_KNLIST_H
+#	include <knlist.h>
+#endif
+
+#ifdef HAVE_KSTAT_H
+#	include <kstat.h>
+#endif
+
+#ifdef HAVE_WINLDAP_H
+#	undef SEC_I_INCOMPLETE_CREDENTIALS
+#	undef SEC_E_INCOMPLETE_CREDENTIALS
+#	undef SEC_I_RENEGOTIATE
+#	include <Winldap.h>
+#endif
+
+#ifdef HAVE_WINBER_H
+#	include <Winber.h>
+#endif
+
+#ifdef HAVE_MACH_HOST_INFO_H
+#	include <mach/host_info.h>
+#endif
+
+#ifdef HAVE_MACH_MACH_HOST_H
+#	include <mach/mach_host.h>
+#endif
+
+#ifdef HAVE_MTENT_H
+#	include <mtent.h>
+#endif
+
+#ifdef HAVE_NETDB_H
+#	include <netdb.h>
+#endif
+
+#ifdef HAVE_SYS_WAIT_H
+#	include <sys/wait.h>
+#endif
+
+#ifdef HAVE_NETINET_IN_H
+#	include <netinet/in.h>
+#endif
+
+#ifdef HAVE_PWD_H
+#	include <pwd.h>
+#endif
+
+#ifdef HAVE_SIGNAL_H
+#	include <signal.h>
+#endif
+
+#ifdef HAVE_STDINT_H
+#	include <stdint.h>
+#endif
+
+#ifdef HAVE_SYS_LOADAVG_H
+#	include <sys/loadavg.h>
+#endif
+
+#ifdef HAVE_SYS_PARAM_H
+#	include <sys/param.h>
+#endif
+
+#ifdef HAVE_SYS_PROC_H
+#	include <sys/proc.h>
+#endif
+
+#ifdef HAVE_SYS_PSTAT_H
+#	include <sys/pstat.h>
+#endif
+
+#ifdef HAVE_PTHREAD_H
+#	include <pthread.h>
+#endif
+
+#ifdef HAVE_SYS_DK_H
+#	include <sys/dk.h>
+#endif
+
+#ifdef HAVE_RESOLV_H
+#	include <resolv.h>
+#endif
+
+#ifdef HAVE_SYS_DISK_H
+#	include <sys/disk.h>
+#endif
+
+#ifdef HAVE_SYS_SOCKET_H
+#	include <sys/socket.h>
+#endif
+
+#ifdef HAVE_SYS_STAT_H
+#	include <sys/stat.h>
+#endif
+
+#ifdef HAVE_SYS_STATVFS_H
+#	include <sys/statvfs.h>
+#endif
+
+#ifdef HAVE_SYS_SWAP_H
+#	include <sys/swap.h>
+#endif
+
+#ifdef HAVE_SYS_SYSCALL_H
+#	include <sys/syscall.h>
+#endif
+
+#ifdef HAVE_SYS_SYSCTL_H
+#	include <sys/sysctl.h>
+#endif
+
+#ifdef HAVE_SYS_SYSINFO_H
+#	include <sys/sysinfo.h>
+#endif
+
+#ifdef HAVE_SYS_SYSMACROS_H
+#	include <sys/sysmacros.h>
+#endif
+
+#ifdef HAVE_SYS_VAR_H
+#	include <sys/var.h>
+#endif
+
+#ifdef HAVE_SYS_VFS_H
+#	include <sys/vfs.h>
+#endif
+
+#ifdef HAVE_SYS_VMMETER_H
+#	include <sys/vmmeter.h>
+#endif
+
+#ifdef HAVE_LIBPERFSTAT
+#	include <libperfstat.h>
+#endif
+
+#ifdef HAVE_SYS_RESOURCE_H
+#	include <sys/resource.h>
+#endif
+
+#ifdef HAVE_NLIST_H
+#	include <nlist.h>
+#endif
+
+#ifdef HAVE_NET_IF_H
+#	include <net/if.h>
+#endif
+
+#ifdef HAVE_NET_IF_MIB_H
+#	include <net/if_mib.h>
+#endif
+
+#ifdef HAVE_SYS_USER_H
+#	include <sys/user.h>
+#endif
+
+#ifdef HAVE_KVM_H
+#	include <kvm.h>
+#endif
+
+#ifdef HAVE_SYSLOG_H
+#	include <syslog.h>
+#endif
+
+#ifdef HAVE_TIME_H
+#	include <time.h>
+#endif
+
+#ifdef HAVE_UNISTD_H
+#	include <unistd.h>
+#endif
+
+#ifdef HAVE_SYS_IPC_H
+#	include <sys/ipc.h>
+#endif
+
+#ifdef HAVE_SYS_SEM_H
+#	include <sys/sem.h>
+#endif
+
+#ifdef HAVE_SYS_SHM_H
+#	include <sys/shm.h>
+#endif
+
+#ifdef HAVE_SYS_FILE_H
+#	include <sys/file.h>
+#endif
+
+#ifdef HAVE_MATH_H
+#	include <math.h>
+#endif
+
+#ifdef HAVE_REGEX_H
+#	include <regex.h>
+#endif
+
+#ifdef HAVE_VM_VM_PARAM_H
+#	include <vm/vm_param.h>
+#endif
+
+#ifdef HAVE_ARPA_INET_H
+#	include <arpa/inet.h>
+#endif
+
+#ifdef HAVE_SYS_MOUNT_H
+#	include <sys/mount.h>
+#endif
+
+#ifdef HAVE_SYS_TIMEB_H
+#	include <sys/timeb.h>
+#endif
+
+#ifdef HAVE_PROCINFO_H
+#	undef T_NULL /* to solve definition conflict */
+#	include <procinfo.h>
+#endif
+
+#ifdef HAVE_LIBCURL
+#	include <curl/curl.h>
+#	if !defined(HAVE_FUNCTION_CURL_EASY_ESCAPE)
+#		define curl_easy_escape(handle, string, length) curl_escape(string, length)
+#	endif
+#	if 0x071004 >= LIBCURL_VERSION_NUM	/* version 7.16.4 */
+#		define CURLOPT_KEYPASSWD	CURLOPT_SSLKEYPASSWD
+#	endif
+#	if 0x071400 <= LIBCURL_VERSION_NUM	/* version 7.20.0 */
+#		define HAVE_SMTP_AUTHENTICATION	1
+#	endif
+#	define ZBX_CURLOPT_MAXREDIRS	10L
+#endif
+
+/* Net-SNMP is used */
+#ifdef HAVE_NETSNMP
+#	define SNMP_NO_DEBUGGING		/* disabling debugging messages from Net-SNMP library */
+#	include <net-snmp/net-snmp-config.h>
+#	include <net-snmp/net-snmp-includes.h>
+#endif
+
+/* LIBXML2 is used */
+#ifdef HAVE_LIBXML2
+#	include <libxml/parser.h>
+#	include <libxml/tree.h>
+#	include <libxml/xpath.h>
+#endif
+
+/* Required for advanced sigaction */
+#ifdef HAVE_SYS_UCONTEXT_H
+#	include <sys/ucontext.h>
+#endif
+
+#ifdef HAVE_ICONV
+#	include <iconv.h>
+#endif
+
+#ifdef HAVE_SSH2
+#	include <libssh2.h>
+#endif
+
+#ifdef HAVE_IO_H
+#	include <io.h>
+#endif
+
+#ifdef HAVE_SYS_MNTTAB_H
+#	include <sys/mnttab.h>
+#endif
+
+#ifdef HAVE_MNTENT_H
+#	include <mntent.h>
+#endif
+
+#ifdef HAVE_DLFCN_H
+#	include <dlfcn.h>
+#endif
+
+#ifdef HAVE_ZONE_H
+#	include <zone.h>
+#	include <utmpx.h>
+#endif
+
+#endif
diff --git a/include/zabbix-3.0/zbxtypes.h b/include/zabbix-3.0/zbxtypes.h
new file mode 100644
index 0000000..7d95b8d
--- /dev/null
+++ b/include/zabbix-3.0/zbxtypes.h
@@ -0,0 +1,173 @@
+/*
+** Zabbix
+** Copyright (C) 2001-2016 Zabbix SIA
+**
+** This program is free software; you can redistribute it and/or modify
+** it under the terms of the GNU General Public License as published by
+** the Free Software Foundation; either version 2 of the License, or
+** (at your option) any later version.
+**
+** This program is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+** GNU General Public License for more details.
+**
+** You should have received a copy of the GNU General Public License
+** along with this program; if not, write to the Free Software
+** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+**/
+
+#ifndef ZABBIX_TYPES_H
+#define ZABBIX_TYPES_H
+
+#if defined(_WINDOWS)
+#	define ZBX_THREAD_LOCAL __declspec(thread)
+#else
+#	define ZBX_THREAD_LOCAL
+#endif
+
+#define	ZBX_FS_DBL		"%lf"
+#define	ZBX_FS_DBL_EXT(p)	"%." #p "lf"
+
+#define ZBX_PTR_SIZE		sizeof(void *)
+
+#if defined(_WINDOWS)
+#	include <strsafe.h>
+
+#	define zbx_stat(path, buf)		__zbx_stat(path, buf)
+#	define zbx_open(pathname, flags)	__zbx_open(pathname, flags | O_BINARY)
+
+#	ifndef __UINT64_C
+#		define __UINT64_C(x)	x
+#	endif
+
+#	ifndef __INT64_C
+#		define __INT64_C(x)	x
+#	endif
+
+#	define zbx_uint64_t	unsigned __int64
+#	define ZBX_FS_UI64	"%I64u"
+#	define ZBX_FS_UO64	"%I64o"
+#	define ZBX_FS_UX64	"%I64x"
+
+#	define zbx_int64_t	__int64
+#	define ZBX_FS_I64	"%I64d"
+#	define ZBX_FS_O64	"%I64o"
+#	define ZBX_FS_X64	"%I64x"
+
+#	define snprintf		_snprintf
+
+#	define alloca		_alloca
+
+#	ifndef uint32_t
+#		define uint32_t	__int32
+#	endif
+
+#	ifndef PATH_SEPARATOR
+#		define PATH_SEPARATOR	'\\'
+#	endif
+
+#	define strcasecmp	lstrcmpiA
+
+typedef __int64	zbx_offset_t;
+#	define zbx_lseek(fd, offset, whence)	_lseeki64(fd, (zbx_offset_t)(offset), whence)
+
+#else	/* _WINDOWS */
+
+#	define zbx_stat(path, buf)		stat(path, buf)
+#	define zbx_open(pathname, flags)	open(pathname, flags)
+
+#	ifndef __UINT64_C
+#		ifdef UINT64_C
+#			define __UINT64_C(c)	(UINT64_C(c))
+#		else
+#			define __UINT64_C(c)	(c ## ULL)
+#		endif
+#	endif
+
+#	ifndef __INT64_C
+#		ifdef INT64_C
+#			define __INT64_C(c)	(INT64_C(c))
+#		else
+#			define __INT64_C(c)	(c ## LL)
+#		endif
+#	endif
+
+#	define zbx_uint64_t	uint64_t
+#	if __WORDSIZE == 64
+#		define ZBX_FS_UI64	"%lu"
+#		define ZBX_FS_UO64	"%lo"
+#		define ZBX_FS_UX64	"%lx"
+#	else
+#		ifdef HAVE_LONG_LONG_QU
+#			define ZBX_FS_UI64	"%qu"
+#			define ZBX_FS_UO64	"%qo"
+#			define ZBX_FS_UX64	"%qx"
+#		else
+#			define ZBX_FS_UI64	"%llu"
+#			define ZBX_FS_UO64	"%llo"
+#			define ZBX_FS_UX64	"%llx"
+#		endif
+#	endif
+
+#	define zbx_int64_t	int64_t
+#	if __WORDSIZE == 64
+#		define ZBX_FS_I64	"%ld"
+#		define ZBX_FS_O64	"%lo"
+#		define ZBX_FS_X64	"%lx"
+#	else
+#		ifdef HAVE_LONG_LONG_QU
+#			define ZBX_FS_I64	"%qd"
+#			define ZBX_FS_O64	"%qo"
+#			define ZBX_FS_X64	"%qx"
+#		else
+#			define ZBX_FS_I64	"%lld"
+#			define ZBX_FS_O64	"%llo"
+#			define ZBX_FS_X64	"%llx"
+#		endif
+#	endif
+
+#	ifndef PATH_SEPARATOR
+#		define PATH_SEPARATOR	'/'
+#	endif
+
+typedef off_t	zbx_offset_t;
+#	define zbx_lseek(fd, offset, whence)	lseek(fd, (zbx_offset_t)(offset), whence)
+
+#endif	/* _WINDOWS */
+
+#define ZBX_FS_SIZE_T		ZBX_FS_UI64
+#define ZBX_FS_SSIZE_T		ZBX_FS_I64
+#define zbx_fs_size_t		zbx_uint64_t	/* use this type only in calls to printf() for formatting size_t */
+#define zbx_fs_ssize_t		zbx_int64_t	/* use this type only in calls to printf() for formatting ssize_t */
+
+#ifndef S_ISREG
+#	define S_ISREG(x) (((x) & S_IFMT) == S_IFREG)
+#endif
+
+#ifndef S_ISDIR
+#	define S_ISDIR(x) (((x) & S_IFMT) == S_IFDIR)
+#endif
+
+#define ZBX_STR2UINT64(uint, string) is_uint64(string, &uint)
+#define ZBX_OCT2UINT64(uint, string) sscanf(string, ZBX_FS_UO64, &uint)
+#define ZBX_HEX2UINT64(uint, string) sscanf(string, ZBX_FS_UX64, &uint)
+
+#define ZBX_STR2UCHAR(var, string) var = (unsigned char)atoi(string)
+
+#define ZBX_CONST_STRING(str) ""str
+#define ZBX_CONST_STRLEN(str) (sizeof(ZBX_CONST_STRING(str)) - 1)
+
+typedef struct
+{
+	zbx_uint64_t	lo;
+	zbx_uint64_t	hi;
+}
+zbx_uint128_t;
+
+#define ZBX_SIZE_T_ALIGN8(size)	(((size) + 7) & ~(size_t)7)
+
+/* macro to test if a signed value has been assigned to unsigned type (char, short, int, long long) */
+#define ZBX_IS_TOP_BIT_SET(x)	(0 != ((__UINT64_C(1) << ((sizeof(x) << 3) - 1)) & (x)))
+
+#endif
diff --git a/src/Makefile.am b/src/Makefile.am
index b39c5aa..57a3d4f 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,9 +1,16 @@
 lib_LTLIBRARIES = libzbxmodbus.la
-
 libzbxmodbus_la_SOURCES = \
 	modbus.c
 libzbxmodbus_la_CFLAGS = $(LIBMODBUS_CFLAGS)
+
+if ZABBIX_2
+libzbxmodbus_la_CFLAGS += -I../include/zabbix-2.4
+endif
+if ZABBIX_3
+libzbxmodbus_la_CFLAGS += -I../include/zabbix-3.0
+endif
+
 libzbxmodbus_la_LDFLAGS = $(LIBMODBUS_LIBS) \
     -module \
     -shared \
-    -avoid-version
\ No newline at end of file
+    -avoid-version
diff --git a/src/modbus.c b/src/modbus.c
index d50ca25..48ae041 100644
--- a/src/modbus.c
+++ b/src/modbus.c
@@ -20,8 +20,8 @@
 #include <sys/ipc.h>
 #include <sys/sem.h>
 
-#include "include/sysinc.h"
-#include "include/module.h"
+#include "sysinc.h"
+#include "module.h"
 
 #include <modbus.h>
 #include <stdio.h>
@@ -35,6 +35,7 @@
 
 #define MODBUS_BIT      'b'
 #define MODBUS_INTEGER  'i'
+#define MODBUS_SIGNED_INT  's'
 #define MODBUS_LONG     'l'
 #define MODBUS_FLOAT    'f'
 
@@ -348,6 +349,11 @@ int zbx_modbus_read_registers(AGENT_REQUEST *request, AGENT_RESULT *result)
     case MODBUS_INTEGER:
         SET_UI64_RESULT(result, tab_reg[0]);
     break;
+    
+    case MODBUS_SIGNED_INT:
+        //use float type in zabbix item
+        SET_DBL_RESULT(result, (int16_t) tab_reg[0]);
+    break;
 
     case MODBUS_FLOAT:
         if (end == MODBUS_16BIT_LE) {