(a) Service -- When required. Except as otherwise provided in this chapter, every order required by its terms to be served, every pleading subsequent to the original complaint unless the court otherwise orders because of numerous defendants, every written motion other than one which may be heard ex parte, and every written notice, appearance, demand, offer of judgment, and similar paper shall be served upon each of the parties. However, the failure of a party to file pleadings in an action shall be deemed to be a waiver by him or her of all notices, including notices of time and place of trial and entry of judgment, and all service in the action, except service of pleadings asserting new or additional claims for relief, which shall be served as provided by subsection (b) of this Code section.

(b) Same -- How made. Whenever under this chapter service is required or permitted to be made upon a party represented by an attorney, the service shall be made upon the attorney unless service upon the party himself is ordered by the court. Service upon the attorney or upon a party shall be made by delivering a copy to him or by mailing it to him at his last known address or, if no address is known, by leaving it with the clerk of the court. As used in this Code section, the term "delivery of a copy" means handing it to the attorney or to the party, or leaving it at his office with his clerk or other person in charge thereof or, if the office is closed or the person to be served has no office, leaving it at his dwelling house or usual place of abode with some person of suitable age and discretion then residing therein. Service by mail is complete upon mailing. Proof of service may be made by certificate of an attorney or of his employee, by written admission, by affidavit, or by other proof satisfactory to the court. Failure to make proof of service shall not affect the validity of service.

(c) Same -- Numerous defendants. In any action in which there are unusually large numbers of defendants, the court, upon motion or of its own initiative, may order that service of the pleadings of the defendants and replies thereto need not be made as between the defendants, and that any cross-claim, counterclaim, or matter constituting an avoidance or affirmative defense contained therein shall be deemed to be denied or avoided by all other parties, and that the filing of any such pleading and service thereof upon the plaintiff constitutes due notice of it to the parties. A copy of every such order shall be served upon the parties in such manner and form as the court directs.

(d) Filing. All papers after the complaint required to be served upon a party shall be filed with the court within the time allowed for service.

(e) "Filing with the court" defined. The filing of pleadings and other papers with the court as required by this chapter shall be made by filing them with the clerk of the court, except that the judge may permit the papers to be filed with him, in which event he shall note thereon the filing date and forthwith transmit them to the office of the clerk.