diff --git a/dxfeed/core/listeners/listener.pyx b/dxfeed/core/listeners/listener.pyx
index a56c6c5..59ea437 100644
--- a/dxfeed/core/listeners/listener.pyx
+++ b/dxfeed/core/listeners/listener.pyx
@@ -31,7 +31,7 @@ cdef void trade_default_listener(int event_type,
             events[i] = TradeTuple(symbol=unicode_from_dxf_const_string_t(symbol_name),
                                    sequence=trades[i].sequence,
                                    price=trades[i].price,
-                                   exchange_code=unicode_from_dxf_const_string_t(&trades[i].exchange_code),
+                                   exchange_code=unicode_from_dxf_const_string_t(&trades[i].exchange_code, size=1),
                                    size=trades[i].size,
                                    tick=trades[i].tick,
                                    change=trades[i].change,
@@ -66,11 +66,13 @@ cdef void quote_default_listener(int event_type,
                                    time=quotes[i].time,
                                    time_nanos=quotes[i].time_nanos,
                                    bid_time=quotes[i].bid_time,
-                                   bid_exchange_code=unicode_from_dxf_const_string_t(&quotes[i].bid_exchange_code),
+                                   bid_exchange_code=unicode_from_dxf_const_string_t(&quotes[i].bid_exchange_code,
+                                                                                     size=1),
                                    bid_price=quotes[i].bid_price,
                                    bid_size=quotes[i].bid_size,
                                    ask_time=quotes[i].ask_time,
-                                   ask_exchange_code=unicode_from_dxf_const_string_t(&quotes[i].ask_exchange_code),
+                                   ask_exchange_code=unicode_from_dxf_const_string_t(&quotes[i].ask_exchange_code,
+                                                                                     size=1),
                                    ask_price=quotes[i].ask_price,
                                    ask_size=quotes[i].ask_size,
                                    scope=<int> quotes[i].scope)
@@ -102,7 +104,7 @@ cdef void summary_default_listener(int event_type, dxf_const_string_t symbol_nam
                                      prev_day_volume=summary[i].prev_day_volume,
                                      open_interest=summary[i].open_interest,
                                      raw_flags=summary[i].raw_flags,
-                                     exchange_code=unicode_from_dxf_const_string_t(&summary[i].exchange_code),
+                                     exchange_code=unicode_from_dxf_const_string_t(&summary[i].exchange_code, size=1),
                                      day_close_price_type=summary[i].day_close_price_type,
                                      prev_day_close_price_type=summary[i].prev_day_close_price_type,
                                      scope=summary[i].scope)
@@ -166,7 +168,7 @@ cdef void time_and_sale_default_listener(int event_type,
                                  event_flags=tns[i].event_flags,
                                  index=tns[i].index,
                                  time=tns[i].time,
-                                 exchange_code=unicode_from_dxf_const_string_t(&tns[i].exchange_code),
+                                 exchange_code=unicode_from_dxf_const_string_t(&tns[i].exchange_code, size=1),
                                  price=tns[i].price,
                                  size=tns[i].size,
                                  bid_price=tns[i].bid_price,
@@ -243,8 +245,8 @@ cdef void order_default_listener(int event_type,
                                    count=order[i].count,
                                    scope=order[i].scope,
                                    side=order[i].side,
-                                   exchange_code=unicode_from_dxf_const_string_t(&order[i].exchange_code),
-                                   source=unicode_from_dxf_const_string_t(&order[i].source[DXF_RECORD_SUFFIX_SIZE]),
+                                   exchange_code=unicode_from_dxf_const_string_t(&order[i].exchange_code, size=1),
+                                   source=unicode_from_dxf_const_string_t(&order[i].source[0]),
                                    market_maker=unicode_from_dxf_const_string_t(order[i].market_maker),
                                    spread_symbol=unicode_from_dxf_const_string_t(order[i].spread_symbol))
         py_data.cython_internal_update_method(events)
diff --git a/dxfeed/core/utils/helpers.pxd b/dxfeed/core/utils/helpers.pxd
index 6cc4cda..9722442 100644
--- a/dxfeed/core/utils/helpers.pxd
+++ b/dxfeed/core/utils/helpers.pxd
@@ -5,6 +5,6 @@ cdef extern from *:
     PyObject * PyUnicode_FromWideChar(dxf_const_string_t w, Py_ssize_t size)
     dxf_const_string_t PyUnicode_AsWideCharString(object, Py_ssize_t *)
 
-cdef object unicode_from_dxf_const_string_t(dxf_const_string_t wcs)
+cdef object unicode_from_dxf_const_string_t(dxf_const_string_t wcs, int size=*)
 
 cdef dxf_const_string_t dxf_const_string_t_from_unicode(object symbol)
\ No newline at end of file
diff --git a/dxfeed/core/utils/helpers.pyx b/dxfeed/core/utils/helpers.pyx
index 4c55b20..c1fd9ec 100644
--- a/dxfeed/core/utils/helpers.pyx
+++ b/dxfeed/core/utils/helpers.pyx
@@ -5,7 +5,7 @@ from dxfeed.core.pxd_include.DXTypes cimport *
 from pathlib import Path
 import dxfeed
 
-cdef object unicode_from_dxf_const_string_t(dxf_const_string_t wcs):
+cdef object unicode_from_dxf_const_string_t(dxf_const_string_t wcs, int size=-1):
     """
     Cython function, callable from C to convert dxf_const_string_t(wchar_t) to unicode
     
@@ -13,6 +13,8 @@ cdef object unicode_from_dxf_const_string_t(dxf_const_string_t wcs):
     ----------
     wcs: dxf_const_string_t, wchar_t
         C string
+    size: int
+        Number of characters. By default -1
         
     Returns
     -------
@@ -21,7 +23,7 @@ cdef object unicode_from_dxf_const_string_t(dxf_const_string_t wcs):
     """
     if wcs == NULL:
       return ''
-    ret_val = <object>PyUnicode_FromWideChar(wcs, -1)
+    ret_val = <object>PyUnicode_FromWideChar(wcs, size)
     return ret_val
 
 cdef dxf_const_string_t dxf_const_string_t_from_unicode(object symbol):
diff --git a/pyproject.toml b/pyproject.toml
index 4051e56..7607b05 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = 'dxfeed'
-version = '0.5.0'
+version = '0.5.1'
 description = 'DXFeed Python API via C API'
 authors = ['Index Management Team <im@dxfeed.com>']
 build = 'build.py'