This number is used for emergency call out. In my case it is for a fire as I am on a volunteer fire crew for work.

This number is part of an automated notification system that calls everyone on a predetermined list, usually as part of some emergency response.  I don't know the company, or how specifically random people wind up on such a list (bad data entry, former employment with a company that used it, etc).  Basically, it will notify the recipient of an emergency, and prompt them to press a number if they plan to respond or not.  In my case, when I am called, it has been used always for simulated scenarios and practice, and never for an actual emergency.  So if you hear something unusual, it's probably not really related to an actual problem.  Wish I could help you more than that.

computer automated call says it's my local police dept (but that wouldn't be 312 area code) and there is a missing person, describes him & to press 1 to accept the call or 3 to not accept (my other half pressed 1 apparently), then a few hours later called back & says missing person has been found, & again press 1 to accept or 3 to not accept the call. very weird & pretty suspect if you ask me. thinking of calling the local police to ask about it.

For those who are getting the calls on your cell phone - put the number in your contacts list and assign it the ring tone "no ring".  It won't stop the calls but it will make them easier to ignore.

cell rings, several times saying emergency response needed, type in number to accept 3 to not accept, I type 3, keeps calling all hours day or night. won't quit. look up shows chicago, down town zone 01, globalcom - phone co. land line shown on the look up.

Received 3 calls in a row from this number within a few minutes.  Answered the call the 1st 2 times, no response.  The 3rd time I let the call go to voice mail.  No message left.

An Internet search shows the Phone Company for this number is Globalcom, Inc.-IL, Telephone # Provider is Winstar Wireless, Inc. and the Phone Equipment Location Code is CHICGOZN01

Today 3-12-09 between 11:26AM and 12:13PM I received a total of nine calls on my cell phone from 312-673-5001, the number displayed on my caller ID.

Each time I answered there was no response.  I called the number and received a message that "all circuits were disabled."  

I recall this had happened about a year ago from the same or similar Chicago-area number but thought nothing of it at the time.  

Hope this helps and am very curious who or what it is.

- Bill in Florida

Same this this morning.  no message, no sound, nothing.
I had number blocked from phone.  I couldn't track down who the phone number belongs to, but they are customer of this phone company: Global com inc, in chicago. I called global come and registered a complaint:
http://www.global-com.com/content.aspx?id=76

Repeated calls from this phone number.  No one responds.