petty@ralvm31.vnet.ibm.com ("Jack Petty") (05/04/91)
In article <422@wybbs.mi.org> rickt@wybbs.UUCP (Rick Tucker ) writes: >I have recently started using v.32 modems and have noticed that >when you terminate the connection(via loging out of the host) >that you get a steady stream of 'the unknown'. >Any way to prevent this? The CCITT defined a "clear-down" signal that a disconnecting modem can send to the modem at the other end to let that modem know that the connection is ending. Use of this specialized re-train signal slows down the disconnect process a bit from the point of view of the DTE that has just dropped DTR or equivalent, but it limits the garbage data at the other end to around 100 characters. We noticed during the development of the IBM 7855 modem that some V.32 modems do not send out the "clear-down" signal when they go on-hook. We also found that most or all will respond to one that comes in from the telco line. If the modems doing the disconnecting (host side I think), offer the GSTN clear-down as an option, it might be worth trying. Of course, using a modem-to-modem protocol as suggested by Greg Andrews would be a cleaner solution. Jack Petty