The CSS is located at IRS/MCC and operates in conjunction with the Information Reporting Program. The CSS provides service to the payer community (financial institutions, employers, and other transmitters of information returns).

The Information Reporting Program CSS answers both magnetic media and tax law questions relating to the filing of information returns (Forms 1096, 1098, 1099, 5498, 8027, W-2G, and W-4). The CSS also answers magnetic media questions related to Form 1042-S. Also CSS answers tax law and paper filing related questions about Forms W-2 and W-3, as well as handling inquiries dealing with backup withholding and reasonable cause requirements due to missing and incorrect taxpayer identification numbers.

The CSS accepts calls worldwide. The new toll-free number to call is 866-455-7438. Callers from outside of the United States must use the phone number 304-263-8700. The Telecommunications Device for the Deaf (TDD) phone number is 304-267-3367. These are toll calls. The CSS can be contacted via email at mccirp@irs.gov. Hours of operation for the CSS are Monday through Friday, 8:30 a.m. to 4:30 p.m. Eastern time. The CSS is in operation throughout the year to handle the questions of payers, transmitters, and employers. Due to the high demand for assistance at the end of January and February, it is advisable to call as soon as possible to avoid these peak filing seasons.