Bob and all, A RS232 normally has no power output to power external devices like USB does. RS232 provides data and other hand shaking lines for control.
The RIB box is simply a RS232 level to 5 volt transceiver converter. RS232 is up to +/-25 V (most are in the 10 V range) logic data and radios are most often 0-5V. The RIB box does the conversion with some hand shaking of the control lines. I have seen some RS232 to 0-5V converters that do not require power for the receive line. A simple inverter made from a NPN transistor will work often...will not meet RS232 spec, but will work. The transmit line is another issue for the computer wants the +/-higher voltages. Often if the RS232 port is not getting correct hand shaking it displays an error such as if no device is connected when the port is accessed. This is in the computer driver. My RIB boxes, some 3rd party, have provisions and require an external power source. I have taken the hand shaking lines and jumpered on the connector to give the computer the right signals. The problem is if the target device cannot handle the speed of the incoming characters...the device takes too much time between characters to handle and the computer simply spits it out on its own speed (we are not talking about baud rate here, but character rate) and the device gets over run. I would think if working on one computer and not another then the one not working is requiring the handshaking on the port and the RIB box is not providing it. 73, ron, n9ee/r >From: "Bob M." <[EMAIL PROTECTED]> >Date: 2008/04/06 Sun AM 04:24:56 CDT >To: Repeater-Builder@yahoogroups.com >Subject: Re: [Repeater-Builder] RIB-less cable circuitry > >On the two Dell computers the RIBless cables don't >work on, a regular battery-powered after-market RIB >works perfectly under MS-DOS. So does anything else I >attach to the serial port. But when the DTR and RTS >lines are low, the RIBless port isn't getting any >power, its circuitry isn't working, and the radio sees >an unpowered RIB attached to its programming line. >Gets nowhere fast. I haven't tried every computer in >the house to see if perhaps RSS is turning those lines >on but my Dell machines aren't doing that, or if RSS >doesn't bother with the lines, in which case it's up >to the computer BIOS to do the job. Since a lot of >older RSS packages don't have good serial port >routines in them, I suspect RSS doesn't even bother >trying to set DTR and RSS. > >I've seen a lot of IBM laptops where the serial port >was disabled or reassigned to be a modem or IR port. >The Dell machines I've got (most are pre-2000) have >the ports assigned properly/logically. > >Bob M. >====== >--- George Henry <[EMAIL PROTECTED]> wrote: > >> I have seen some Dell laptops where the serial port >> was disabled in the BIOS >> right out of the box, but still works under Windows >> XP. You might want to >> check the BIOS settings to be sure the port is >> actually enabled. >> >> George, KA3HSW / WQGJ413 >> >> ----- Original Message ----- >> From: "Bob M." <[EMAIL PROTECTED]> >> To: <Repeater-Builder@yahoogroups.com> >> Sent: Saturday, April 05, 2008 8:00 PM >> Subject: Re: [Repeater-Builder] RIB-less cable >> circuitry >> >> > Thanks. That's what I was looking for. >> > >> > The reason I'm investigating this is that a friend >> > bought several RIBless cables to program GTX >> radios. >> > We used one on his Compaq laptop and it worked >> just >> > fine. We then tried to use one on two other >> computers >> > - both DELL - and the RIB seemed dead, as in no >> power. >> > The GTX thought the RIB was turned off and came up >> in >> > trunking test mode. We had to use a real RIB and >> cable >> > to finish the job. >> > >> > So I bought one of those LED testers for DB9 ports >> and >> > found low signals on DTR and RTS, as well as TXD >> > during idle periods. Starting RSS didn't change >> the >> > state of those lines, and as they're the ones that >> are >> > providing power, the RIBless cable is dead in the >> > water. >> [snip] > >__________________________________________________________ >You rock. That's why Blockbuster's offering you one month of Blockbuster Total >Access, No Cost. >http://tc.deals.yahoo.com/tc/blockbuster/text5.com > > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
