HDLC Link management ... (SABM & UA) ???

i use RCM6700 for HDLC. (Serial F)

between two rabbit module, hdlc working very well.

but .between rabbit and another hdlc device,

occur problem.

the problem occur in the following flow.

  1. another hdlc device send SABM message to rabbit.

    SABM (Set Asynchronous Balanced Mode)

  2. rabbit send UA message to another hdlc device.

    UA (Unnumbered Acknowledgement)

as above… after sending the UA message …

rabbit do not receive any data.

so… check rx_data pin using oscilloscope.

rx_data signal moves.

What is the problem ???

I would not know how to debug. ㅜㅜ