أنشئ حسابًا أو سجّل الدخول للانضمام إلى مجتمعك المهني.
well it really depends on the situation. If we think that the ext / intercome is important that time, than we must excuse to our customer and answer the call but if call doesn't seems important than we should deal with the customer first or to pick up the call and let him hold for a while and than deal with the customer.