Johannesburg is 7 hours ahead of Boston (EST) or 6 hours ahead (EDT). When it's 9:00 AM in Boston, it's 4:00 PM in Johannesburg. South Africa does not observe DST.
Boston uses ET (Eastern Time) while Johannesburg uses SAST (South Africa Standard Time).
Optimal window: 7:00 AM - 11:00 AM Boston time (2:00 PM - 6:00 PM Johannesburg). Early morning calls from Boston reach afternoon business hours in Johannesburg.
Boston universities have partnerships with South African institutions in research and development.