peter@stca77.stc.oz (Peter Jeremy) (01/16/89)
I have been having problems with serial ports shutting down with the message "Garbage or loose cable on serial port xx, port shut down". This has occurred on two different machines (ITT PS/440 and IBM PS/2), but only on ports talking to modems. I am running Xenix/286 2.2.1 on both machines. In both cases, the modems were powered from the same supply as the computer and the cables appear satisfactory. (The modems are leased lines and the TelCo reports that the modems are working normally). The problem only shows up at one end of the circuit as well. Has anyone else had similar problems? Does anyone know of a fix? -- Peter Jeremy (VK2PJ) peter@stca77.stc.oz Alcatel-STC Australia ...!uunet!stca77.stc.oz!peter 41 Mandible St peter%stca77.stc.oz@uunet.UU.NET ALEXANDRIA NSW 2015
wain@seacbc.UUCP (Wain Dobson) (01/21/89)
In article <392@stca77.stc.oz> peter@stca77.stc.oz (Peter Jeremy) writes: >I have been having problems with serial ports shutting down with the message >"Garbage or loose cable on serial port xx, port shut down". This has occurred >on two different machines (ITT PS/440 and IBM PS/2), but only on ports talking >to modems. I am running Xenix/286 2.2.1 on both machines. > Ran into the same problem. Did not investigate it to the core; however, I was using a Cardinal modem. I simply went back to my US Robotics. Since, I have not had time to pursue the problem, I am *assuming* that the message arises from the "intelligent" firmware on the Cardinal. But, this is only a wild guess. And, probably, I'm quite off base. -- Wain Dobson ...!{uunet,ubc-cs}!van-bc!tessera!seacbc!wain
rac@jc3b21.UUCP (Roger A. Cornelius) (01/21/89)
From article <392@stca77.stc.oz>, by peter@stca77.stc.oz (Peter Jeremy): - I have been having problems with serial ports shutting down with the message - "Garbage or loose cable on serial port xx, port shut down". This has occurred - on two different machines (ITT PS/440 and IBM PS/2), but only on ports talking - to modems. I am running Xenix/286 2.2.1 on both machines. - - In both cases, the modems were powered from the same supply as the computer - and the cables appear satisfactory. (The modems are leased lines and the - TelCo reports that the modems are working normally). The problem only shows - up at one end of the circuit as well. - - Has anyone else had similar problems? Does anyone know of a fix? - -- - Peter Jeremy (VK2PJ) peter@stca77.stc.oz - Alcatel-STC Australia ...!uunet!stca77.stc.oz!peter - 41 Mandible St peter%stca77.stc.oz@uunet.UU.NET - ALEXANDRIA NSW 2015 This happens to me occasionally when I turn the power off to a modem while the port is still enabled. After 30 minutes the port should work again (I read this somewhere, but haven't timed it). This has only happened on tty1A, and I've had two different modems on that port at different times. tty2A also has a modem, but I've never had the problem there. My fix is just to remember to disable the port before messing with the power switch on the modem. Roger Cornelius sherpa!rac
felix@netmbx.UUCP (Felix Gaehtgens) (01/21/89)
In article <392@stca77.stc.oz> peter@stca77.stc.oz (Peter Jeremy) writes: >I have been having problems with serial ports shutting down with the message >"Garbage or loose cable on serial port xx, port shut down". This has occurred >on two different machines (ITT PS/440 and IBM PS/2), but only on ports talking >to modems. I am running Xenix/286 2.2.1 on both machines. i've seen these problems too several times and all i did was just disabling and enabling the port again. this seemed to work. i couldn't find ANYTHING wrong with the modem or the cables, though. eventually, the problem disappeared. i'd like to know what really caused this message though, and a fix too (if thereis one) so long, felix -- BANG: ..pyramid!tub!netmbx!xaos!felix SMART: felix@xaos.sub >In as much as a number of excellent hallucinogens already exist, I would not >reccomend going to the trouble of extracting the adrenal gland from living >humans. I personally also have ethical problems with this procedure ....
peter@stca77.stc.oz (Peter Jeremy) (01/24/89)
In article <392@stca77.stc.oz>, I wrote: > I have been having problems with serial ports shutting down with the message > "Garbage or loose cable on serial port xx, port shut down". This has occurred > on two different machines (ITT PS/440 and IBM PS/2), but only on ports talking > to modems. I am running Xenix/286 2.2.1 on both machines. All of the replies have assumed that I was talking about login ports on smart modems. As I stated in my original article, the problem is occurring on _leased-line_ (totally dumb) modems. These modems are used to transfer data between a continuously running application on the PC and another computer. Getty is not involved. Following some study of the _siointr routine in the kernel, as well as applying rapid pulses to the various control lines, I have ascertained that the system is highly resistant to noise when the non-modem invocation of the serial port is used. Since the incoming control lines (CTS, DSR, DCD) are unnecessary for my application and the outgoing control lines are valid whether modem or non-modem ports are specified, I have switched to using the non-modem ports. So far I have had no problems, but since it is an intermittent fault, I will only ever know if I didn't solve the problem. -- Peter Jeremy (VK2PJ) peter@stca77.stc.oz Alcatel-STC Australia ...!uunet!stca77.stc.oz!peter 41 Mandible St peter%stca77.stc.oz@uunet.UU.NET ALEXANDRIA NSW 2015