A subpoena is an order of a court which requires a person to be present at a certain time and place or suffer a penalty (subpoena means, literally, “under penalty”). This is the traditional tool used by lawyers to ensure that witnesses present themselves at a given place, date and time to make themselves available to testify.
What is substituted service?
If a party appears to be avoiding service of court documents, a request may be made with the court to, instead of personal service (i.e. giving the document directly to the person), that the document be published in a local newspaper, served on a person believed to frequent the person or mailed to his (or her) last known address.