Interfacing

General

The program can interface with your radio using several ports from the computer. These ports are:

• Serial port - With a serial port it is possible to send CW, key PTT or communicate with your radio. Most computers nowadays have one Serial communication port with 9. Laptops mostly have one serial port but sometimes no serial port at all. When there is no serial port (available) a USB to serial converter can be used.
• Parallel port - With the parallel port it is possible to send CW and key PTT at the same time. There is additional info available on the parallel port. With this additional info you can switch antennas with the right interface connected. Also there is a pin that indicates which radio is currently active.
• USB port - The USB port can be used with a USB-to-serial converter. Not every USB-to-serial converter can send CW. Also devices like the microHAM - microKEYER or the Ham Radio Solutions - EZmaster can be used but have far more capabilities than just being a serial port converter. See the chapter Supported Hardware for more information.
• Sound card - The sound card is used to send sound (Wav) files to your radio for instance for giving CQ and for sending and receiving when using RTTY with MMTTY. The sound card can also be used to record all the QSOs you are making.

For CW the parallel and serial ports are assumed to have the default addresses shown in the list below. These addresses can be changed in the configurer to match your Windows setup.

These addresses used in Windows can be checked in (Win98) 'Control Panel | System | Device Manager | Ports (COM & LPT) | (Choose a port) | Resources | Input Output Range'.

Nonstandard port addresses will not work for CW.

Tip. If you have one standard and one non-standard COM port, assign the non-standard to the radio, and the standard port to CW.

Radio interfacing

Interfacing to a radio is done directly with a serial cable (straight or crossed) or when using an older radio an additional interface is needed. Every brand has it's own solution for it, also they have there own commands when changing frequency, changing band etc. So always look in the manual what to use with your radio to get it connected. When a direct serial cable is needed be sure it has all the necessary pins wired. A cable with full wiring is mostly ok but sometimes a cable with only 3 wires could be the way to go..   When using an additional interface there are two choices again. You buy the original for your radio or you build one yourself. When you buy an original interface the manual will say what kind of cable you need for it. When you make an interface yourself or buy a not original interface it can be that you are in trouble. The program determines if you have to use a cable with only three wires (software handshaking) or five wires (hardware handshaking).

CW key and PTT interfacing

Via Parallel port

Below a picture of a possible interface.

Parallel (LPT) port

• Pin 1 - Strobe
• Pin 16 - PTT output
• Pin 17 - CW output
• Pin 18 - Ground

Via Serial Port

Note. The CW- and(!) the PTT-line have to come from the same serial/parallel port. Example: When COM4 e.g. is the CW-Port the PTT-line has to be connected at the same jack

Using a transistor

• Equivalents for the 2N2222 are 2N3904, BC547 or BC548.
• NB. It isn't a bad idea to add a 1 kOhm resistor from base to ground, also adding a shunt capacitor of 10 nF is highly recommended at the collector output to ground in order to prevent RF feedback to base and subsequent blocking.

Using an optocoupler

By Brian Kassel, K7RE

As the serial port spec is to have -12 and + 12 on the DTR pin,  a diode needs to be put in series with the 470 ohm resistor that drives the LED on the input to the OPTO-Isolator.  The cathode (banded) end goes toward the OPTO-Isolator. A transistor could be used here, but I like the OPTO-Isolator route, as it affords more protection to  the serial port in case something down stream  from the port goes awry.  You still need to protect the active device in your interface from the negative voltage though. Some notebook serial ports don't have a negative voltage, so you may be all right there, BUT if you switch out the interface to a PC that does, you are in for trouble.
BTW, no negative voltage appears at parallel (LPT / printer) ports, so no negative voltage protection or isolation is needed there.

Via USB port

Not all computers have serial ports anymore or not enough to control transceivers, packet, serial CW keying etc. In this case consider a USB to serial port adapter. Most of them do nicely control the radio. The problem with these interfaces is doing CW and/or PTT (and 5 bit codes). Test before or ask around if they work for radio control, CW or PTT control with your computer and radio! Also look first if drivers for your operating system are available.

With N1MM CW will work with native serial ports and with USB-to-serial adapters. For perfect CW not dependent on Windows processes the answer is Winkey by K1EL. CW transmitted as normal ASCII characters via the serial port. A USB/serial adapter will work fine with K1EL, because it is standard serial communications. Check the Winkey manual for more information.

In some cases PTT does not work well when using USB to serial. Check this Windows setting:

• Control Panel; System Icon,
• Hardware Device Manager Tab or button.
• Expand USB Serial Bus Controllers
• Highlight each USB Root Hub
• Double click for Properties settings, Power Management tab,
• Remove the check mark from 'Allow the computer to turn off this device to save power'.
  • The box is checked by default in most cases.
• Reboot the computer

A very nice overview of serial- USB converters can be found at the RTTY contesting page by AA5AU at: http://www.rttycontesting.com/us

Additional Parallel Port Interfacing

If the type of CW port chosen is LPT1, LPT2 or LPT3, additional information will be present on the chosen parallel port. In configurer select for which Radio the output has to be given on the selected port (Radio 1 or Radio 2). The BCD data on the LPT is that of the current active radio/VFO. The band data is available on multiple LPT ports -- Radio 1 on LPT1, Radio 2 on LPT2 and so on.

NB. When DVK is selected, the Antenna selection via the LPT port is disabled. The DVK pins and the antenna pins on the LPT port overlap.

Parallel port pin layout

Band decoder output

Sample configs

Sample config two stacked antennas

Sample config for switching between two stacked antennas with an automatic antenna switch. This diagram assumes that the decoder emits positive DC voltages from each terminal.

Attach the upper antenna to terminal one, and the lower antenna to terminal two. When the program outputs code 1, the upper antenna will be selected. When the program the program outputs code 2, the lower antenna will be selected. When the program outputs code 0, both antennas will be selected. Note that 0 is the lowest code, so both antennas will be the default.

The picture below shows the configuration in the Configurer.

Bearing data

Bearing data for rotator control is currently not available on the LPT port.

Sound card interfacing

Its better to run the mic through the sound card all the time. That way your audio sounds the same either recorded or live. It also lets you re-record cq's on the fly, something that is really needed for 40m and 80m split cqing.  Check out "#1 - Zero or Single Card, One radio, No Sound Card SO2R " which can also be found with more examples in the SO2R section.

#1 - Zero or Single Card, One radio, No Sound Card SO2R

One radio and one sound card to play wav files and record new messages and mute the microphone when playing wav files.
Select '1 - Single Card - One radio, No Sound Card SO2R' on the 'Audio' tab in the Configurer and setup the top part of this dialog.
The sound is centered rather than set to a radio channel.

Another possible soundcard interface.

This is NOT the preferred method any more!

Sound card DVK

• A 8:1000 ohms transformer should be used when the sound card speaker output is used to the radio microphone input.
• A 600:600 ohms (1:1) transformer should be used when the line output from the sound card is used to the radio microphone input.

Serial and Parallel port interfacing under Windows NT/2000/XP

Windows NT, Windows 2000, XP and their descendants require a special dll which will be installed by running: PORT95NT.EXE to use the parallel, serial and USB ports.
Windows 95, 98 (SE), ME don't need this special dll. In these operating systems N1MM logger can access the parallel port direct without the need for an extra driver.

To install the NT/2000/XP capable dll, do the following:

• Download PORT95NT.EXE. A link to this file can be found in the installation section.
• The size is about 1,6 Mb.
• To install, just run port95nt.exe
  • Select Next, Yes and typical where appropriate.
  • Yes to boot your PC
  • You are done.
• You have to be the administrator of your machine when running port95nt.exe

Everything on one COM port

By Uffe PA5DD.

Shared ports allow for example Radio control/PTT/PTT-interrupt/CW on just one COM port, which might be all you have on your laptop. It requires that you make a serial splitter or a common interface. There are some pitfalls though:

• Radio control communication is without hardware handshake (as you are using the hardware control pins for other purposes). This is not a problem as such, since hardware handshake is not used by your radio. True at least for ICOM & YAESU.
• Some interfaces wire RTS/CTS together to allow a PC set for hardware handshake to work properly. This link must be removed for port sharing, as it will generate a permanent PTT interrupt on the CTS pin. This will abort your messages as soon as you start them. Also DSR should not be connected to anything.
• In some radio control serial level converters the handshake signals are used as power supply. This is not possible if both RTS & DTR are used for CW/Other. You will have to provide power supply from somewhere else (I use the PS/2 mouse port). Note that in this case you only have to split out GND TXD RXD for the radio control.

I need more serial ports

By Didier KO4BB

Interrupts are the limiting factor to more than a handful of serial (com) ports. There are 2 ways to address that:

1) You want to use "standard" hardware using Windows "standard" com port model, and as long as the software will let you select IO port and IRQ, and as long as you don't need parallel printer or floppy (and as long as your video card does not use IRQs also), and if the program lets you share IRQs (for instance, you don't need an IRQ for a serial port used to drive the PTT line), (that's a lot of if's!!!) you can probably cram 4 to 6 com ports into a single PC. Note that you may still have problems if you try to run high bit rate on all the ports at once (that should not be a problem with radio control though). Please note that the "standard" PC setup (and Windows) supports 4 com ports with only 2 IRQs. Those who have tried know that you don't want to run high bit rate on COM 1 and COM 3 at the same time because they share the same IRQ.

2a) You do away with standard hardware, and then you can use specialty boards that have 4, 8 or even 16 ports. However, these boards use communication processors so they only need one IRQ from the PC but your software needs to be aware of and be able to communicate with that processor, either through custom software, or through a driver for your OS (Operating System i.e. Windows), or both. That's what ISPs use to gang a bunch of modems to support more than a couple phone lines/modems with each PC. While these may have high communication rate capabilities (because the communications processor uses FIFOs, small memory buffers that store incoming data until the PC is ready to take it), they also offer higher latency (response time) than a native port, not ideal for CW, although with a fast PC, most users have been satisfied with this setup.

2b) USB adapters fall in the category of non-standard hardware, but because USB is now built into the motherboard, the communication processor hardware is directly supported by the BIOS, and the OS has the proper drivers, so that has quickly become a standard. However, the USB standard was not designed to minimize latency, so a USB-serial adapter, while OK to talk to a radio via it's serial port, is not ideal to do things such as CW using bit twiddling. That should be reserved to native serial or parallel ports (motherboard or add-on card). USB adapters are probably a little worse (with regard to latency and CW capability) than custom communication processors described at 2a) because the USB adapters communicate with the PC through a serial link instead of being directly connected to the processor bus, so the bit twiddling has to be done though a serial link, which adds latency. In addition, since the USB port may be shared with other devices, accessing these other devices while sending CW would be a bad thing.

Bottom Line: There are excellent USB combination interfaces now available that can control one or more radios, key them with Winkey, and even provide soundcard facilities.

Hooking up a Footswitch

A footswitch can be hooked up to a serial and a parallel port. Thefootswitch program action is for both LPT and COM ports on switch closure.

Parallel port

Hooking up a footswitch to LPT1 can be done by connecting a 10k resistor from pin 14 to pin 15 of LPT1. Pin 14 is +5V (see note below). Then connect a normally open footswitch between pin 15 and pin 18 of LPT1. Closing the footswitch pulls pin 15 low and performs the function selected in the configurer.
Note: pin 14 also used for Radio A/Radio B control of external boxes, so that it won't always be +5 volts . If this is the case an external +5 V power supply can be used.

Serial port footswitch information (using the 9 pin connector numbers)