ugmarkj@sunybcs.UUCP (Mark D. Johnson) (01/16/85)
[ Where did that clutter on my screen come from? ] A short while ago I posted an article asking for help about my Qubie 1200 baud modem. I kept getting line noise, causing garbage on my screen. Going on the responses I got, it seems that the Qubie is not such a great buy for the low price after all. It seems to perform well at 300 baud, but that it not what I bought it for. I would also like to thank all who responded to tell me that it is not just my problem, but a flaw in the Qubie design. (I strongly doubt my problem is caused entirely by noisy phone lines - I had been using a 300 baud modem with another micro for 2 years without this sort of problem.) I have since made arrangements to replace the Qubie with a Hayes 1200b! Appended below is a summary of my mailbox, intended to help any potential modem purchasers. Mark J. ====================================================================== Sometimes the VADIC which we use at 1200 will generate spurious characters on some phone connections. I would guess that there is crosstalk which the modem interprets as characters. The solution has been to re-make the telephone connection, hoping to get either a quieter line or modem on the other end. ========================================================================= I've been using this modem for a bit more than a year now. It doesn't work too well. (But I spent the money, so I'm bearing it.) In addition to the noise you mentioned (usually only in the evenings) it has great difficulty in making its first connection. Sometimes I have to try 3 or 4 times. I get the tone from the host, but my modem won't answer. And sometimes it hangs - the only way out is cycling the power. I find that the noise problem only occurs in the evening, and so I have always assumed that it is my Telco's problem. If others are having this problem with Qubie modems (and not with other modems) then I guess the problem must be Qubie's. ========================================================================= I bought a QB last year at this time and had problems. I exchanged it and got another that performed equally poorly. The solution to the problem was to return the QB and buy a Hayes. After the frustration of using the QB, the extra $100 seemed well worth it. My opinion is that a design flaw and/or low tolerance components cause the QB to lose phase lock of the recieved signal very easily. The result is frequent strings of random characters. Noise on the line causes occaisional "{" characters to appear. If you get random bursts of junk, it's the modem. ======================================================================== I am not familiar with the QUBIE 1200, however, I have a Racal Vadic modem and also experienced some severe noise problems at home. I later discovered that my problem was caused by my wireless phone. Unplugging the phone from the jack while the modem was in use cleared up the noise problem. Secondly, the phone company does not guarrantee the phone lines for data connections unless you so specify. In other words, for the cost of another phone line Ma Bell will assure you of a noise free connect to any other phone hhaving a noise free connection. ======================================================================== I have been using my QUBIE plug in board in my IBM PC for almost a year. I have never had a problem with garbage, though with Signalman 300 baud it was terrible. The only problem I have hadd is the damn thing answering the phone on voice calls, or answereing on no call. I'm happy with it, especially at the price. ======================================================================== Mark - I almost bought the same modem as you did; not wanting to pay the amount for an overprice Hayes S martmodem. When I called to buy it at a well known place (I beleive it was compu-add ) they said they had just dropped it because 50% of them were being returned. It seems that they work fine at 300 baud but don't cut the mustard at 1200. I would try to return it as soon as poosible and get one of the low priced Hayes compatables. (Password etch...). ======================================================================= I don't know much about the Qubie, but the problem may not be with the modem. Do you really get extraneous characters, transmitted characters that got mutilated, or dropped characters? Depending on which of these symptoms you have, you ought to look for different problems: SYMPTOM LIKELY CAUSE Mutilated characters Modem Extra characters, especially Line during quiet intervals. Dropped characters The terminal emulation program may be having trouble keeping up at 1200 baud. ========================================================================= I have a Prometheus Promodem 1200 and am experiencing similair problems of the extraneous char. variety. mainly I recieve extra {'s (only at 1200). I sent the modem back for a replacement and still am having the same problem but to a slightly lesser degree. this time I sent it back to the manufacturer to see what they may be able to do. 1/3 of the connections I get are totally poor, and the rest of the time I average 1 garbage char. per 1 to 2 min. I suspect the problem is a combination of poor noise filtering by the modem and poor university 1200 baud modem connections. ========================================================================== Mark D. Johnson SUNY/Buffalo Computer Science uucp: [decvax,dual,rocksanne,watmath,rocksvax]!sunybcs!ugmarkj ARPAnet, CSnet: ugmarkj%buffalo@CSNET-RELAY