Dan Henry wrote:
-------------------------------
They may have limitations as to how frequently you can dial the same number over and over in the case of no connection if there is no human involved in the initiation and termination of auto-dialing (i.e., a device that decides to dial out of its own initiative and is out of the control of a human supervisor).

Steve, Andy, Jez, etc. would know better than me, but I seem to recall when adapting a security related system design for use in the U.K., the issue of "blacklisting" where if a particular number was auto-dialed repeatedly, the PSTN "blacklisted" that number at the calling end for some period of time. This was in the mid-80's and my memory is fuzzy about the details (what with all the tumblers of Scotch between then and now), but I remember having to add a second phone number to the dialing procedure to break up the persistent sequence.