I'm not sure what it is. I find the description rather confusing. At first I don't understand what the word "parallel" shall mean in the headline. Then it is called "null modem" but has a male connector. A null modem cable is used to connect two computers to each other and a computer usually has a male connector, so the null modem cable needs female connectors. Also the description talks about connecting serial devices to the adapter. This is not done with a null modem cable. A serial null modem cable is similar to a crossover Ethernet cable, i.e. it has the sending and receiving lines crossed so that two computers can talk to each other. A device is usually connected to a computer by a 1:1 connection without crossed lines.
So what I suppose from the description is that the device is just a serial to USB adapter, i.e. it adds a serial port to a PC which does not have one. And when I scroll further down the page to the "most watched items" I see many similar adapters with much cheaper prices.
I entered a search for "usb null modem" and the first one found was this:
http://cgi.ebay.co.uk/USB-RS232-Serial-Null-Modem-Cable-DB-9-Pin-Lead-/390097022555?pt=UK_Computing_CablesConnectors_RL&hash=item5ad3982e5bIt looks much more promising to me. It's a serial to USB adapter and a serial null modem cable. I am quite sure that this would work. And it's a few pence cheaper also.
Edit: sorry, I forgot that you also need a 9-to-25-pin adapter. This certainly nullifies the price advantage. Also it seems that all those cables are sold either by Printstar or by Computerstar which both look much like the same seller. I would prefer to be able to compare descriptions from different sellers. Don't you have an electronics store in the neighborhood where you can ask? Or a preferred electronics online shop (other than ebay) with better product descriptions?
