relationship between "call" and "send"

[Ben Rubinstein]

What is the relationship between "call" and "send"?  I can see that send can
take some optional extra parameters for scheduling - apart from that are
they fundamentally different?

TIA,
 
  Ben Rubinstein               |  Email: benr_mc at cogapp.com
  Cognitive Applications Ltd   |  Phone: +44 (0)1273-821600
  http://www.cogapp.com        |  Fax  : +44 (0)1273-728866