Sorry for the delay.  I have been slowed by a broken wrist.  Yes, I operated a PCBoard in such a network for srveral years, and expect to find documentation about this method online.  If the doctor has good news tomorrow, probably I'll have the power during the week to organoze a proper reply in [[Talk:QWK (file format).  Meanwjile no big deal whether this historical detail is in or out of the article.