On Fri, Mar 29, 2019 at 12:25 PM Thomas Morehouse <[email protected]> wrote:
> Thanks gents. Being new to the 102 - USB game, I find that every step of > the way needs another adapter gizmo. And the correct male/female connector > for the gizmo is often an unexpected "gotcha". > > For some reason I'd thought that the serial-usb cable would eliminate the > need for the null modem. Live and learn. > > There's more than one way to do it. I bought several Belkin Serial Laplink cables at some point. They have the proper "null modem" wiring built in. I just use it with a gender changer at the M100 end since the M100 uses a female gendered port (the gender is independent of the wiring). As to which end to put a null modem adapter on a straight through cable, it doesn't matter. Just be careful not to confuse gender changers with null modem adapters. As to the serial-usb obviating the null modem, no. There are two wirings: DTE and DCE. Data Terminal Equipment (computers, terminals) and Data Communications Equipment (modems). Serial usb, just like a built in serial port as the M100 has, are wired as terminals, DTE. Modems are wired as DCE. DTEs are made to connect directly to DCE. When you connect a Host (terminal) to another Host (terminal) you have to swap the wiring effectively making the peer look like a DCE wired device. That's how I think about it. If you have two hosts, you need to make one of them look like a modem. You can do that with a null modem wire cable, or you can use a straight through cable and a null modem adapter. -- John.
