“…Our circuit design is inspired on closely related experimental and theoretical work that has been carried out on forced astable multivibrators, some of which has even used the same 555 timer chip employed here [Allen, 1983a,b;Tang et al, 1983]. In particular, we followed the works of [Guisset et al, 2007;Ramírez-Ávila et al, 2003Ramírez-Ávila et al, , 2007Ramírez-Ávila et al, , 2011Ramírez-Ávila et al, , 2010Rubido et al, 2011aRubido et al, , 2009Rubido et al, , 2011b, in which oscillators based upon the 555 IC are coupled through light. In these articles, the system behavior has been extensively studied from the point of view of phase-response curves, phase dynamics, noise influence, and Arnol'd tongues; and not only for the master-slave situation, but also for mutual-interaction.…”