705 ILCS 310/9.1
In single county circuits, the chief judge of the circuit court of the county shall certify to the clerk of the court the number of petit jurors required each month. The clerk shall then repair to the office of the jury commissioners and there, in the presence of the persons mentioned in Section 8 of this Act, proceed to draw by lot the necessary number of names from those made available for such drawing as in Section 8 of this act provided. The clerk shall thereupon certify the electors whose names are so drawn and summon them by the procedure he selects or is directed by the court to select from among those permitted by this Section.
The issuing clerk may use first class mail as the initial form of summons, incorporating any reasonable form of request for acknowledgement which is deemed practical and which would provide a reliable proof of service. One permissible method is the use of a duplex card properly addressed to the person summoned to be a juror and requesting the person so summoned to detach and return to the issuing clerk the part of the duplex card which is attached for his acknowledgement with his signature thereon. As used in this Section, a "duplex card" means any postcard with 2 mailable parts with a summons on one part and a detachable acknowledgement of receipt of such summons on the other part. If the person summoned to be a juror does not return the acknowledgement of the summons in the time period requested, such prospective juror shall not be deemed guilty of a contempt of court.
The issuing clerk may use certified mail as the initial means of service or as a secondary means of service in case the acknowledgement requested in a summons delivered by first class mail is not returned in the time period required. The certified mail may or may not be marked for delivery to the addressee only. The certificate of the issuing clerk that he has sent the summons pursuant to this Section is evidence that he has done so.
If service of summons cannot be made by the type of service selected, the clerk shall reissue such summons and deliver it to the sheriff for service as provided in such case in Section 9 of "An Act governing jurors, and to repeal certain Acts as provided in such therein named," approved February 11, 1874, as amended. If more jurors are needed during the month, a judge of the court shall so certify, and they shall be drawn and certified forthwith in the manner above provided. Whenever a grand jury is required by law or by order of the court, it shall be drawn and certified in like manner.
705 ILCS 310/9.1