Hi, I have some questions about HDLC controllers: 1. Is there any standard protocol that I have to follow? is the ITU-T Q.921 is the one? 2. what CRC should I use CRC-16? 3. what is the flow control protocol should I follow and how? Thanks Jamil Khatib __________________________________________________ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/