Thanks a lot, I got the cable and worked right.
Jed Clear wrote: > On Fri Jun 5 9:55 , Cesar Bonilla sent: > >> Jed Clear escribió: >> >>> On Thu Jun 4 10:58 , Cesar Bonilla <cesar.boni...@hyettemail.com> sent: >>> >>>> I have a Net5501 with a USB Memory. I connect to Console port but I >>>> can't see anything! >>>> >>>> > [snip] > >>>> >>>> >>> Are you using a null modem cable (pins 2 and 3 crossed)? >>> >>> Also it might be worth giving 9600 a shot, in case it's not quite factory >>> fresh. >>> >> I found many diferent types of cable: >> > > Most of these will work in many cases. > > >> Null modem without handshaking >> 2 - 3 >> 3 - 2 >> 5 - 5 >> > > The first one is the bare minimum (Tx, Rx, Ground) with the key feature of the > pin 2-3 crosses. This works if both devices ignore their hardware flow control > inputs, which is often the default. For 9600 and 19200, you can generally get > away w/o flow control. > > >> Null modem with loop back handshaking >> 2 - 3 >> 3 - 2 >> 5 - 5 >> 1 + 4 + 6 - NONE >> NONE - 1 + 4 + 6 >> 7 + 8 - NONE >> NONE - 7 + 8 >> > > This one should work, but the local loopbacks only "cheat" the hardware > handshaking and provide no flow control. You could get overrun errors at the > upper speeds (e.g. 115,200). > > >> Null modem with partial handshaking >> 1 - 7 + 8 >> 2 - 3 >> 3 - 2 >> 4 - 6 >> 5 - 5 >> 6 - 4 >> 7 + 8 - 1 >> > > I'm very suspicious of this one. Generally you want DCD (1) to be driven by > DTR > (4), not RTS (7), if at all. Who ever came up with this probably had hardware > flow control disabled anyway. > > >> Null modem with full handshaking >> 2 - 3 >> 3 - 2 >> 4 - 6 >> 5 - 5 >> 6 - 4 >> 7 - 8 >> 8 - 7 >> > > This should work the best for most cases. > > >> I'm confusing. Can you say me what pins connect to other side? >> > > Welcome to the confusing world of cheating on the RS-232 "standard". The > standard was designed to let data terminal equipment (DTE), such as a dumb > terminal or server (and now a PC), talk to data communications equipment (DCE, > i.e. a modem). Almost immediately people began using the RS-232 ports on two > pieces of DTE to direct connect without modems. So they had to figure out > how to > get around the handshaking designed to talk to a modem. Since many ways will > work in various cases, you get many solutions. > > If you're the curious type, and want to fully grok what's going on, you can > find > out more starting here http://en.wikipedia.org/wiki/Flow_control and here > http://en.wikipedia.org/wiki/RS_232#Conventions. If you just want to build a > cable and move on, go with the last configuration. > > However, my personal favorite is: > 2 - 3 > 3 - 2 > 5 - 5 > 4 - 6 + 1 > 6 + 1 - 4 > 7 - 8 > 8 - 7 > > But in practice I haven't picked up a soldering iron in ages. I just keep > around > a handful of DE9 gender bender and null modem inserts. > > -Jed, Grey Beard Hardware Engineer > > > _______________________________________________ > Soekris-tech mailing list > Soekris-tech@lists.soekris.com > http://lists.soekris.com/mailman/listinfo/soekris-tech > >
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