I have purchased two AC4790-xxxx modules and they are not communicating well or at all?

Answer

The SLOCK 0 and SLOCK 1 settings in the AC4790 EEPROM configuration control how a receiving radio synchronizes and communicates with a transmitting/broadcasting radio, considered Sessions. The length of the Session is dependent on the Session Count setting and which value the local radio loads to its Current Session Counter in order to determine the length of the Session, 1 Session Count = 1 hop time or 20ms. There are 4 possible Session configurations which are chosen using the SLOCK 0 and SLOCK 1 bits (Address Location: 0xC1, bit 4 and 5. The 4 states are: SLOCK 0 SLCOK 1 Session Actions RX/TX or Broadcaster 0 0  Receiver loads its Current Session Counter with its Session Count value.  TX/Broadcaster loads its Current Session Counter with its Current Session Count. 0 1  Receiver loads its Current Session Counter with its Transmit Retries + Session Count.  TX (Broadcaster) loads its Current Session Counter with its Transmit Retries + Session Count (Broadcast Attempts + Session Count). --Last two Session settings are only valid for Transmitters not Broadcasters- 1 0  Receiver loads its Current Session Counter with the remote radio's Session Count.  TX loads its Current Session Counter with the remote radio's Session Count. 1 1  Receiver loads its Current Session Counter with the remote radio's Current Session Counter value.  TX loads its Current Session Counter with the remote radio's Current Session Count The ideal SLOCK 0/1 settings for a simple Point-to-Point network is the last Session Type in the table above, SLOCK 0 = 1 and SLOCK 1 = 1. However, the Default AC4790 EEPROM Configuration is set to use the 3rd Session Type in the table above, SLOCK 0 = 1 and SLOCK 1 = 0. For a Point-to-Point network set SLOCK 1 = 1, from a default configuration state, on both AC4790 radio's and retest communications.