No caller ID characters, no message.  Presume they are spammers.

Called for the second time.  Now their caller ID characters are "RESRCH STDY".  Obviously these are people are scofflaws.

Second time that this company has called in two hours. I chose to speak to a representative and told her that our number is on the federal Do Not Call Registry, that I had already requested to be removed from the call list once today, and that I was filing a second complaint against them with the FTC.

Called at 4pm on 6/7/13.    Was a robocall recording of a male voice offering participation in testing a gout treatment, promising compensation if I qualify.   Caller ID showed "Resrch stdy."  Following is the message left on my answering machine:

"….a love one diagnosed with gout, a local physician in  your area  is conducting a research study and for those who qualify, compensation may be available.  That's right,  you may be eligible for compensation just for participating in this free study.   If you have not had a heart attack or stroke in the last twelve months, you or a love one may be eligible to participate in a new study with this most recent treatment to relieve gout attacks.  If you would like to learn more about this opportunity, please press one to speak to one of our representatives; or press two, to be taken off our list."

No identifying info of any kind was given.  So non-specific, and vague, it's an obvious con.   Filed a complaint with FTC.

Stop calling my number, for your information my number is P R I V A T E next call you are going to pay for it I reported your number to AT&T.