jas@mulga.oz (John Shepherd) (06/23/87)
Thanks for your replies so far. Unfortnuately, I got the original question a little bit wrong. The correct description is: On a VAX 11/780 under VMS 4.5 a terminal logged onto the Vax selects the function to SET HOST/DTE/DIAL(etc) to dial out another port which has a modem attached. This is used to log onto another Vax. If the user does a CONTROL-\ to return to the local host, the session between the two modems remains, even when the user has logged off the local machine. The next user of the modem gets the session. We would rather have some mechanism for making the local modem hang up in ther=se situations. We have tried doing the following in the hope of disabling control signals and convincing the local modem to hang up: SET TERM/NOMODEM <modem port> WAIT 00:00:02 SET TERM/MODEM <modem port> How do we get the local modem to hang up? Training users to log off the remote system is not a reliable solution, and some of these modem connections are (unfortunately) overseas links.
carl@CITHEX.CALTECH.EDU.UUCP (06/28/87)
> On a VAX 11/780 under VMS 4.5 a terminal logged onto the Vax selects the > function to SET HOST/DTE/DIAL(etc) to dial out another port which has a modem > attached. This is used to log onto another Vax. If the user does a CONTROL- > to return to the local host, the session between the two modems remains, even > when the user has logged off the local machine. The next user of the modem > gets the session. We would rather have some mechanism for making the local > modem hang up in these situations. The mechanism exists and works properly on my system, and should work on any system using a DZV11, DHV11, DZ11, DZ32, DMF32, DMB32, DHU11, DMZ32, LAT, or VAX 8200 serial lines as the terminal interface. > We have tried doing the following in the hope of disabling control signals > and convincing the local modem to hang up: > SET TERM/NOMODEM <modem port> > WAIT 00:00:02 > SET TERM/MODEM <modem port> Well, that's a start, since it means that you've normally got the terminal set /MODEM. However, I can't find anything in the documentation that says that setting a terminal /NOMODEM affects the signals the VAX sends to the modem; it simply says that if the terminal is set /NOMODEM, the VAX will ignore all incoming modem signals. On the other hand, there IS a setting documented to drop modem control signals under certain circumstances. Quoting from the "Terminal Driver" section of the VAX/VMS I/O User's Reference Manual: Part I, section 8.2.3.2: By default, logging out on a line with modem signals will not break the connection. If TT2$M_HANGUP is set, modem signals are dropped when the process logs out. If TT2$M_MODHANGUP is set, no privilege is required to change the state of TT2$M_HANGUP. By setting TT2$M_HANGUP, system managers can prevent nonprivileged users who are not logged in from tying up a dial-in line. Actually, when referring to the behavior of terminals, the manual should be talking about "when all channels have been deassigned" rather than "when a user logs out", since what they say applies to both cases, and the latter is a subset of the former. > How do we get the local modem to hang up? You should try setting the terminals connected to the dial-out modems /Modem/Hangup/Dialup/Permanent. This means that the system will pay attention to modem control signals at all times, and will drop DTR when it is deallocated (if the user didn't explicitly allocate the terminal, assigning a channel to it implicitly allocates it). I'm not sure whether the /DIALUP characteristic is necessary; at one time, it had an effect on whether /NOHANGUP would do anything. > Training users to log off the remote system is not a reliable solution, and > some of these modem connections are (unfortunately) overseas links. Note: Your users could easily get in the habit of allocating the dial-out terminal before issuing the "SET HOST/DTE" command, so as to permit them to return to the local machine without losing their connection (since the terminal's still allocated, it has a channel assigned, and won't drop DTR). If this happens, then you'll probably start seeing them occasionally forget that they have the terminal allocated, and tie up the line (with or without the phone call still going on) for hours on end.