I heard from someone that I might be able to use the UART pins on the teensy for this (then use said teensy to interpret & reprogram the layout to your liking) but an off-the-shelf serial to USB converter might work.
http://www.pjrc.com/teensy/td_uart.html
I heard from someone that I might be able to use the UART pins on the teensy for this (then use said teensy to interpret & reprogram the layout to your liking) but an off-the-shelf serial to USB converter might work.
http://www.pjrc.com/teensy/td_uart.html
It looks like there are only 3 wires coming off the plug.
I see various "power" and "ground" connections elsewhere, but it doesn't look like there is any power being supplied to the device.
This has been something that I have wondered about. It would be great if I could fabricate another adapter for my Teensy box.
edit - wait, is the power coming in through those 2 LEDs? What are they for, anyway?
The 5 volts is coming from the usb/teensy.
So "Data" and "Clock" are more or less self-powered? I am accustomed to seeing that 4th wire (Vcc, 5V, whatever) coming off the keyboard plug.
I am not very well-versed in electronics.
Name | Abbr. | Pin |
Transmitted Data | TxD | 3 |
Received Data | RxD | 2 |
Data Terminal Ready | DTR | 4 |
Data Carrier Detect | DCD | 1 |
Data Set Ready | DSR | 6 |
Ring Indicator | RI | 9 |
Request To Send | RTS | 7 |
Clear To Send | CTS | 8 |
Signal Ground | G | 5 |
Limitations of the standard:
No method is specified for sending power to a device. While a small amount of current can be extracted from the DTR and RTS lines, this is only suitable for low power devices such as mice.
The standard specifies a maximum open-circuit voltage of 25 volts: signal levels of ±5 V, ±10 V, ±12 V, and ±15 V are all commonly seen depending on the voltages available to the line driver circuit. Some RS-232 driver chips have inbuilt circuitry to produce the required voltages from a 3 or 5 volt supply.'
I'd probably recommend opening the case and seeing what actual wires are connected to the serial plug. I'd guess you'd probably only have pins 2(data) pin 5(gnd) and the remain pins would be what was used to power it.It's not great, but it's all I have:
It's not great, but it's all I have:Show Image(https://farm4.staticflickr.com/3849/14700843108_69b77fe655_h.jpg)
I see 5 pins connected. Full album: https://www.flickr.com/photos/dork_vader/with/14700843108/
It's not great, but it's all I have:Show Image(https://farm4.staticflickr.com/3849/14700843108_69b77fe655_h.jpg)
I see 5 pins connected. Full album: https://www.flickr.com/photos/dork_vader/with/14700843108/
Do you have a multimeter to test which pins they are connect to on the serial connector (assuming a DB9)?
If you don't have it any more then I wouldn't worry about it. Each board has the potential to be different. So unless you plan on working on it now then there is no real need.It's not great, but it's all I have:Show Image(https://farm4.staticflickr.com/3849/14700843108_69b77fe655_h.jpg)
I see 5 pins connected. Full album: https://www.flickr.com/photos/dork_vader/with/14700843108/
Do you have a multimeter to test which pins they are connect to on the serial connector (assuming a DB9)?
I will check, but I think I may no longer have the cable / pcb / case.
As to tools and test equipment, I definitely have what I need for most things.
Lemme see if I have it right.
1) If I am lucky (and I might be, since my serial trackpad is not a complicated device involving multiple LEDs and needing power from multiple pins), some of the 9 pins on the serial cable are actually not connected and not used.
a. If I am that lucky, I would have just pins 2 for data, pin 5 for ground, and presumably 1 pin for power.
b. If that lucky, I can just connect the pins to the teensy and hope that they work.
2) If I am not so lucky which is usually the case with Gutz, the voltage outputted by the teensy won’t be enough for the numpad. I will need a voltage driver chip in between, that spider-looking thing in Dorkvader’s linked photo that lies between the teensy and the device. Not to mention there is no standard way of wiring these things up, so I can’t just expect Soarer’s teensy diagram to work on a serial numpad.
It's entirely possible that you can just get one of these with a driver for your OS (most seem to come with windows drivers)
http://www.expertgps.com/usb-to-serial-adapter.asp
The device uses standard DB-9 pin assignments, ready to be connected you
your host computer. In order to provide power for the keypad, it is recommended
that the host software drive both DTR and RTS high (+4 to +15v).
Pin Name DB-9 Comment
Receive Data 2 Data from PC to keypad [Note 1]
Transmit Data 3 Data from keypad to PC
DTR 4 Set high to supply power
Ground 5 Ground
RTS 7 Set high to supply power
Note 1: Although there is no data transmission from the host computer to the keypad, the
keypad still requires a connection to the host TX pin (pin 2). This is to provide a negative
voltage bias so that the keypad can provide a true RS-232 voltage swing on the keypad
data out (pin 3).
Ahem, all a RS232 to USB adapter does is providing a serial port. The USB class driver creates a virtual serial port inside the OS that software can use like it would a "real" serial port. And yes, these work under Linux (Windows needs an INF file linking the adapter w/ Windows USB CDC ACM driver -- sort of native support.) What you really want is a converter that knows that the serial device it's talking to is some form of keyboard and then presents it as a keyboard on the USB side of things. It has to be DIY, the PRJ project is a good start on how to hook up and program the Mega32U4 serial port.Thanks for the good post as always: lots of good info here. You're like a gold mine.
Edit: after a 2nd glance, above's PRJ example is only good for how to hook up the MAX232 chip (unless you want to use the Arduino libs.) Programming the serial interface isn't that hard tho. As for USB CDC, it's basically this stuff (http://www.pjrc.com/teensy/usb_serial.html).
rowdy, for connecting a serial terminal to a modern PC, you will need a few connectors. First, you need a null modem adapter to connect to the terminal's modem port. Then you need a serial cable, of course. Then run that into a Serial-to-USB adapter, which gives you a serial port on your PC. That's it, as far as the physical connection goes. You may need a gender changer or DB25-to-DB9 adapter in there, too, depending on your setup.
Now, getting the Linux box to speak to the terminal is something else altogether. Luckily, your terminal is a VT220, with backward compatibility to VT100. You can probably find instructions on how to make your PC communicate with the console terminal by searching Google. Although, most of what you will find is for older versions of Linux, which has some features that have been deprecated in modern distros. But it's definitely possible. jwaz got his VT220 working with a RPi running Raspbian. I never could get my WYSE 60 terminal working reliably.
Well, I got close to getting the WYSE console to work under Ubuntu. But the protocol is different enough that it wouldn't work reliably. The serial connection with a USB serial adapter worked just fine, however.
My main query was whether a serial terminal, such as a VT220, would Just Work (tm) through one of the adaptors I listed, or whether anyone has a particular adaptor they know Just Works (tm) in a similar situation.
My main query was whether a serial terminal, such as a VT220, would Just Work (tm) through one of the adaptors I listed, or whether anyone has a particular adaptor they know Just Works (tm) in a similar situation.
Yep, it should "Just Work (tm)" :) The serial port on these adapters is fully featured, as is the virtual com port created by the class driver .
Probably using chinese clones of FTDI chips (http://www.ftdichip.com/Products/ICs/FT231X.html), yes.
On a side note, while looking up FTDI I stumbled across this: Watch That Windows Update: FTDI Drivers Are Killing Fake Chips (http://hackaday.com/2014/10/22/watch-that-windows-update-ftdi-drivers-are-killing-fake-chips/)...
I thought that I used to be able to use these, but maybe that was just for mice and other simple peripherals.
Also, as I look at them, the gender seems wrong being female-female.
Nov 25 20:09:39 carbon kernel: [2160862.136199] usb 4-4: new full speed USB device using ohci_hcd and address 2
Nov 25 20:09:39 carbon kernel: [2160862.301628] usb 4-4: configuration #1 chosen from 1 choice
Nov 25 20:09:40 carbon kernel: [2160862.435107] usbcore: registered new interface driver usbserial
Nov 25 20:09:40 carbon kernel: [2160862.435139] USB Serial support registered for generic
Nov 25 20:09:40 carbon kernel: [2160862.435197] usbcore: registered new interface driver usbserial_generic
Nov 25 20:09:40 carbon kernel: [2160862.435202] usbserial: USB Serial Driver core
Nov 25 20:09:40 carbon kernel: [2160862.441364] USB Serial support registered for ch341-uart
Nov 25 20:09:40 carbon kernel: [2160862.441572] ch341 4-4:1.0: ch341-uart converter detected
Nov 25 20:09:40 carbon kernel: [2160862.464579] usb 4-4: ch341-uart converter now attached to ttyUSB0
Nov 25 20:09:40 carbon kernel: [2160862.464616] usbcore: registered new interface driver ch341