Thanks. It can be seen here, it&#x27;s just 8 bits, highest three are there called NR, so they were 011, lowest 4 were 0001 which means RR receive ready.<p><a href="https:&#x2F;&#x2F;www.tapr.org&#x2F;pub_ax25.html" rel="nofollow">https:&#x2F;&#x2F;www.tapr.org&#x2F;pub_ax25.html</a><p>Fig. 7 -- S frame control fields