116. (1) The convening officer, the president of the court, the judge advocate, or the commanding officer of the accused person may, by summons under his hand, require the attendance, at a time and place to be mentioned in the summons, of any person either to give evidence or to produce any document or thing. (2) In the case of a witness subject to service law the summons shall be sent to his commanding officer and such officer shall serve it upon him accordingly. (3) In the case of any other witness, the summons may be served in such manner as may be prescribed or may be sent to the magistrate within whose jurisdiction he may be or resides and such magistrate shall cause service of the summons as if the witness were required to appear or produce the document or thing in his own Court. (4) When a witness is required to produce any particular document or thing the summons shall describe it with reasonable precision.