[17671]

Hey Guys. We use a Serial radio device at work, it has a very short wire on the end of it and it connects into the Serial Port of our PC or LAptop (Com1).

One of us will need to move the radio a distance away from our computer, and the only way we can accomplish this is to use some sort of Serial Extension cable.

I went to 4 different computer stores and NOT ONE of them carry this. I've been sold the incorrect cable or adapter 3 times now and I'm getting very frustrated and at this point I just want it to work and not run around pulling whats left of my hair out to get this to work lol.

The laptop has a Serial Port, its called Com 1, it has a male connector. My Serial radio has a Female connector, that plugs into it, and there is 2 screws we are suppost to tighten, but we never do because this is not a hand tighten connectir, it requires a screw driver to tighten so we leave it alone and it seems to hold.

What kind of cable goes inbetween there to simply "extend" the connection so we can move it further?

The last guy sold me a m/m gender changer and told me I could use an existing serial modem cable and it will work, well it didn't, and I think the cable has to do with it, its not simply the connector, but there are 2 types of serial cables i believe, i have no idea whats what.

Any ideas?

 

[JamesK]

A normal straight through M/F cable should work. Those things used to be common in the days of external dial up modems. Have you tried Sayal? They used to have a lot of that sort of thing. They're located on Matheson, just west of Dixie.

If that cable doesn't work by itself, try it with the original cable, in case the original does something non standard.

BTW, using the screws is recommended, just don't crank them down tight. Often, without the screws, a connector will loosen and cause problems.

 

[Jake]

The old modem cables I think had the TX and RX pins swapped (called a null modem cable). What you need is a DB9 M/F straight/extension cable.

I may be dating myself but I spent way too much time fiddling with the 25 pin and 9 pin serial connector and configuring the COM ports. Now there was a reason to pull out your hair. In fact I have a large box of these buggers in my basement.

 

[timlocke]

I remember throwing out boxes of those things as well and fiddling with both crimpers and even a soldering iron on those DB connectors.
IIRC the "crossover" tx/rx was often accompanied by stuff like RTS to CTS and so-on.
Straight through were common. Your PC was usually configured as a DTE ( T for terminal) and your external device was configured as a DCE ( C for communication)( and it was not that common) straight through was it. IIRC many non-modem devices were DTE and needed that null modem. If one was lucky one could get away with a cable that only had tx/rx & ground.

 

[JamesK]

The old modem cables I think had the TX and RX pins swapped

The old modem cables did not have the Tx & Rx swapped. That only happened when connecting to DTEs (Data Terminal Equipment, i.e. computer or terminal) together. A normal cable would have each pin on a male connector connected to the same pin number on the female at the other end. The exception would be when a 9 pin male was used at one end and a 25 pin female at the other, when connecting a computer with a 9 pin serial port, to a modem with a 25 pin connector. There have, however, been many devices that didn't follow convention for pin numblers. When connecting to DTEs together, you indeed have to cross Tx & Rx and possibly also loop back some of the control and status signals, so that each DTE thinks it's connected to a DCE, instead of another DTE. When you do that, you have what's referred to as a "null modem".

 

[JamesK]

DB connectors

Only 25 pin connectors are "DB". The 9 pin connectors are "DE". The "D" refers to the connector series and the 2nd letter (B, E, A etc.) the shell size.

D-subminiature connectors

 

[Jake]

Only 25 pin connectors are "DB". The 9 pin connectors are "DE"

But they are most likely labelled DB9 ... so I would look for that.

however, been many devices that didn't follow convention for pin numblers. When connecting to DTEs together, you indeed have to cross Tx & Rx and possibly also loop back some of the control and status signals, so that each DTE thinks it's connected to a DCE, instead of another DTE

And we complain about HDMI cross compatibility.

 

[JamesK]

^^^^
That depends on where you shop. Industrial suppliers use the correct designations. Consumer level vendors often don't. Back when I was in planning at Unitel, I used to buy connectors by the thousands and used the correct term.

Buying a "DB9" is sort of like walking into a lumber yard and asking for a 2x4 that's 6" wide.

 

[Jake]

Hey Paolo do you need 1000 or 1?

 

[cgrc76]

Seeing as no one has said where to get a cable from try monoprice

 

[Steve0]

Not sure what kind of length you need, but I would probably start here:

Blackbox Canada

Good luck

 

[Jake]

The Source have them for sure. Search site for "DB9 MALE TO DB9 FEMALE"

 

[17671]

i was actually at TheSource... By Circuit City, they looked everywhere and did not have what i need. They said they only carry "hot" items lately, but when they used to be "radio shak" back in the day, they would carry literally everything even hard tofind stuff. i guess times are really changing and no one really likes to carry hard tofind items anymore cus it does not make them money.

Jake, i only need one cable. im gonna return this friggin m/m connector tonight, and get my money back. it didnt work.

 

[Jake]

Strange. I just searched postal code L4W 4T4 (I pulled one from random) and all 20 of The Source stores listed stock (not 1 or 2 but 3 and 4). Stock number is: 2600117.

But it does not surprise me. My local Source usually takes a few days to find the items I want. I ask for the item, get the we can't find it answer, then ask if they could call me when they do inventory. I usually get a call at the beginning of the week telling me THEY FOUND IT!

 

[JamesK]

The Source would be the last place I'd look for something like that. You're better of at a computer store. You could try Canada Computers, at Eglinton & Mavis or, as I mentioned earlier, Sayal.

 

[17671]

tried souce canada computers and not sayal thou, found it at AA.. sad to say, canada computers does not know what they r talkoin about, well atleast one guy there, say they are phasing out serial ports, and they stopped carrying them, while AA carries them, i think canada computers only wants to sell hot ticket items thats why, go figutr,

 

[JamesK]

^^^^
He's right. Many computers don't have serial ports anymore and haven't for years. My 8 year old ThinkPad doesn't have one, so I had to buy a USB-serial port adapter.

 

[ScaryBob]

They also stopped selling them because the profit margin disappeared. I remember when a serial cable cost $60 but once surplus stores started selling them for $2 that signaled the end. I've still got a DB25 M-F serial extension and a "Centronics" parallel printer cable that goes with it. Haven't used them for years even though my printer takes both USB and parallel. I would try local or online surplus stores before going to one of the high priced chains. I still use the serial port on my PC for a USB Robotics external fax modem. Many modern PCs still have a serial port header on the motherboard but the adapter required to use it is not installed.

 

[JamesK]

^^^^
I still have a USR Courier on my desk, but it's been years since it's even been powered up. When I first bought it, it was capable of a blazing 14,400 b/s (16.8 if connected to another Courier), but after updates became a V.42 modem that could do 56k down and 33.6 up.

 

[17671]

the problem with big box chains are not required to carry legacy items. back in the old days, if you needed a hard to find item or electronic part, you would go to radio shack, those days are over, they dont exist anymore, stores all they wanna do now is carry hot ticket items only, and worry about their profits.