Wrong byte values when receiving multicast

[ArnoldMonk]

Hi,
following problem / phenomena exists...

My message transmitter sends messages (using ip*works mcast-component). When receiving the messages (using same mcast-component), some byte values are systematically changed.

This happens between values 128 - 159 (dec), below is an example of sent and received values. I think this is supposed to be trivial but can't get forward... I'm using unsigned char buff[] -buffers in both ends.

Thanks in advance,
Arnold

-----------------
ok from 0 ->...
127 127
128 172 !
129 129
130 26 !
131 146 !
132 30 !
133 38 !
134 32 !
135 33 !
136 198 !
137 48 !
138 96 !
139 57 !
140 82 !
141 141
142 125 !
143 143
144 144
145 24 !
146 25 !
147 28 !
148 29 !
149 34 !
150 19 !
151 20 !
152 220 !
153 34 !
154 97 !
155 58 !
156 83 !
157 157
...
ok -> 255