pbickers@groucho (11/14/90)
I have a 16-port Digiboard serial IO board on a Magnum 3000 Unix workstation. These things provide 16 RJ45 connector jacks into which one plugs a 10 wire modular cable (looks like phone line, and apart possibly from the number of wires probably is). On the other end of this modular cable one attaches a modular to DB25 converter and plugs it into whatever peripheral device one desires -- modem, terminal, printer... One can buy made-up cables of 1 foot length for $6.50 + 40c for each extra foot. Because I want to connect a variety of stuff, modems, printers and terminals, some of which will be located in a different room up to maybe 100 or 150 ft away, the exact distance via conduit etc being difficult to determine -- which is part of the problem -- it seems to make sense to buy the RJ45 plugs, cable and converters separately and make up the cables ourselves. I have in mind here to run the modular cable right up to the peripheral rather than changing to ordinary serial line close to the workstation. The question then is: how long can my modular cable be before I start running into problems with signal attenuation or timing factors? Is there a strong reason for making a cable change close to the workstation? (For those who may be thinking of doing this themselves I note that a possible problem is the need for a $700 tool, a crimper/knuckle-press type of thing for the RJ45 plugs. However our technician assures me that he has a tool capable of the job and he has done this before for a PC. I also know the wiring for the converter, or at least I have docs which tell me, which should be the same thing :-) .) -- Paul Bickerstaff Internet: pbickers@neon.chem.uidaho.edu Physics Dept., Univ. of Idaho Phone: (208) 885 6809 Moscow ID 83843, USA FAX: (208) 885 6173