  For networks of pulse-coupled oscillators with delayed excitatory coupling,
we analyze the firing behaviors depending on coupling strength and transmission
delay. The parameter space consisting of strength and delay is partitioned into
two regions. For one region, we derive a low bound of interspike intervals,
from which three firing properties are obtained. However, this bound and these
properties would no longer hold for another region. Finally, we show the
different synchronization behaviors for networks with parameters in the two
regions.
