LimeSDR USB clock synchronisation

A year ago, I purchased a LimeSDR-USB 1v4s board with a USB type A connector. During its use, the following problem occurs.
The prospect arose in anticipation of two LimeSDR-USB 1v4s boards. For these purposes, according to the description, connectors J19 (reference clock input) and J18 (reference clock output) are used. However, in the description of the Lime Suite program, the purpose of controlling the LimeSDR-USB 1v4s board, it does not indicate how to transmit (receive) clock pulses to the J19 and J18 connectors. The tests performed show that there are no pulses at the output of connector J18. The search for the issuance of clock pulses on connector J18 through the tabs of the Lime Suite program did not give a positive result.

  1. Can you please tell me how, using the Lime Suite program, it is possible to issue clock pulses from the J18 connector, which will allow you to synchronize two LimeSDR-USB 1v4s boards?
  2. If the Lime Suite program does not allow you to manage the recovery mode of 2 LimeSDR-USB 1v4s boards, then with what (what software product) is it possible to do this?