Logo of <a href="https://en.wikipedia.org/wiki/Callan_Data_Systems" class="extiw" title="en:Callan Data Systems">Callan Data Systems</a>
Callan Data Systems
Own vectorization, adapted from <a rel="nofollow" class="external text" href="https://ia803208.us.archive.org/12/items/Callan_Data_Systems_Unistar_200_Multiuser_System/Callan_Data_Systems_Unistar_200_Multiuser_System.pdf">front cover of manual</a>