ART100@PSUVM.BITNET ("Andy Tefft 862-6728", 814) (01/10/89)
I have had great success transferring files via null modem cable from my //c to a friends IBM PC clone. I used 19200 baud, and the limit on the speed I could really transfer files seemed to be only caused by disk read/write delays. Wish I had had a ramdisk/hard drive on the clone. I used both Zlink and Kermit 3.84 at 19200 baud. Kermit was quite a bit slower for two reasons: It read the disk more often, and seemed to have more overhead (I used Kermit protocal on Kermit and XMODEM on Zlink. I also wish there were YMODEM on the clone at the time!). For a 30K GIF file, throughput was about 6000-7000 baud (measured in actual data bits/second, assuming 8-bit characters). Kermit was about half as fast. It was quite interesting to watch! By the way, what I used as a null modem cable was a "null modem adaptor" from radio shack (Male db-25 on one end, female on the other). This connected directly (well almost) to the back of the clone (needed a female-female adaptor, too, but this was around because it was needed to hook up his modem), and my regular //c modem cable was connected to the adaptor. I was gonna make myself a null modem cable, but it would have cost me $6 plus soldering plus some way to protect the wires (wasn't going to buy hoods for those db-25's! at $2 apiece), and the adaptor was only $8 anyway. if anyone wants wiring diagrams for a null modem cable, I believe I have some. the basic idea of it is to switch all send-receive pairs (i.e. SD of one end goes to where RD would be on the other end). It's a great way to transfer files like GIF files and text files between computer brands/ disk formats. It was even convenient enough to take my //c over to the friend's house that has the IBM, instead of just calling up and transferring via modem. Andy
jmj@mhuxu.UUCP (J. M. Johnson) (01/10/89)
I once transferred a very large database data file from a IIe to an IBM clone.
On the clone I used a very primative com program to capture the information
from the serial port. On the IIe I wrote a short basic program that opened
the file I wanted to transfer and formatted the data. The data file was going
from ProFiler on the apple to Professional File on the clone. The file was
stored on a Sider hard disk. Between the machines I used a straight through
cable with a null modem adapter and a DB25 to DB9 adapter to plug into the
clone. Professional File had a utility for importing ASCII files with given
delimiters. In all it took about 3 hours for the transfer and about 45 min.
to import the file.
--
Life's just a game, you fly a paper plane, there is no end. - TBA
J. M. Johnson, AT&T Bell Laboratories, Reading, PA ...!att!mhuxu!jmjaash@ms.uky.edu (aashi deacon) (01/11/89)
This may sound silly, but will a printer cable work for a modem? I mean it fits, but is it right? I tried it and for some reason couldn't get the //c to recognize the modem. -- aash aash@ms.uky.edu All things are relative. It just takes a great mind to relate them.
SEWALL@UCONNVM.BITNET (Murph Sewall) (01/11/89)
>This may sound silly, but will a printer cable >work for a modem? I mean it fits, but is it >right? I tried it and for some reason couldn't >get the //c to recognize the modem. A perfectly logical question, and you'll *love* :-) the answer. The short version is a printer cable is different from a modem cable (you can take one end apart and switch the wires on pins 2 and 3 or buy a "null modem" cable for $12-$20). The long version is 1 - a printer is an OUTPUT device, while 2 - (you guessed it) a modem is an INPUT device The reason (yes, Virginia there IS one) is that modems date back to the days before personal computers when COMPUTERS communicated through modems to terminals (as in the Latin for "the end") which (to the host) looked like (tah tah) printers (the first modem probably sent output to a remote printer - the keyboard probably came later). So, the cable is wired so your PC is a PRINTER from the modem's end! 9600 baud sure looks fast to someone who thought 110 baud on a 33 KSR (a MECHANICAL teletype, aka TTY) was pretty neat (and not THAT MANY years ago either). Murph Sewall Vaporware? ---> [Gary Larson returns 1/1/90] Prof. of Marketing Sewall@UConnVM.BITNET Business School sewall%uconnvm.bitnet@mitvma.mit.edu [INTERNET] U of Connecticut {psuvax1 or mcvax }!UCONNVM.BITNET!SEWALL [UUCP] -+- I don't speak for my employer, though I frequently wish that I could (subject to change without notice; void where prohibited) According to the American Facsimile Association, more than half the calls from Japan to the U.S. are fax calls. FAX it to me at: 1-203-486-5246
sloan@tel.inrs.CDN (David Sloan) (01/12/89)
> This may sound silly, but will a printer cable > work for a modem? I mean it fits, but is it > right? I tried it and for some reason couldn't > get the //c to recognize the modem. Your question is not so silly. On my II GS I use an Apple IIe to ImageWriter II cable to connect to my modem. The printer end (circular 8 DIN) plugs into the GS while the computer connector (DB 25) pugs into the modem. David
ALBRO@NIEHS.BITNET (01/13/89)
This is for (aash@ms.uky.edu) in regard to using a printer cable for a modem. N No, it won't work. The problem is RS232 pin 20, which needs to go to port pin 1, but doesn't in the printer cable. This is called "handshake out" by Apple, DTR by everyone else. In the printer cable, this pin (at the port) is connected to DSR/DCD or not connected at all. In the printer cable, RS232 pin 20 (DTR) is connected to port pin 2 (handshake in), so the modem and printer cables are reversed. The printer cable will act like a "null modem" since it also reverses the signal in/out leads, and if your serial port ignores DTR and DSR you can use it that way.
shawn@pnet51.cts.com (Shawn Stanley) (01/14/89)
aash@ms.uky.edu (aashi deacon) writes: >This may sound silly, but will a printer cable >work for a modem? I mean it fits, but is it >right? I tried it and for some reason couldn't >get the //c to recognize the modem. Some printer cables will work with some modems and computer setups. Generally, though, the cabling just isn't right for it. One thing you could try is switching pins 2 and 3, since they're switched on printer communications. You probably can't do that on your //c though... >-- >aash >aash@ms.uky.edu > >All things are relative. It just takes a great mind to relate them. All things are relative. All relatives are things. My relatives took all my things. --Omni contest, 8-9 years ago... UUCP: {rosevax, crash}!orbit!pnet51!shawn INET: shawn@pnet51.cts.com
reeder@reed.UUCP (Doug Reeder) (02/01/89)
In article <10866@s.ms.uky.edu> aash@ms.uky.edu (aashi deacon) writes: >This may sound silly, but will a printer cable >work for a modem? I mean it fits, but is it >right? I tried it and for some reason couldn't >get the //c to recognize the modem. Yes. I have often used my IIc to imagewriter II cable to connect the modem port to a Mac SE. I don't even need an adapter. -- Doug Reeder USENET: ...!tektronix!reed!reeder Box 971 BITNET: reeder@reed.BITNET Imperial University from ARPA: tektronix!reed!reeder@berkeley.EDU Trantor Box 971 Reed College,Portland,OR 97202