Necessities for communication over RS-232.


Here you will find what's needed to connect your tape recorder to your computer using RS-232.


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windows
I have windows too.

 

 

 
Hi-tech loopback device
Loopback test: Pins 2 and 8 at the recorder end are connected.

The tape recorder.

Most tape recorder types A8nn and C27n come with a 9 pin D-sub (DB-9) connector. The Studers need to be equipped with a serial remote controller 1.810.751. The Perl script works with this controller only. This controller and the DB-9 connector may be missing. Also, a different controller may be installed, the serial remote controller 1.820.751. The latter implements the SMPTE/EBU standard over RS232/RS422. The perl script does not work with this controller.

In order to use RS-232, there are a number of jumpers and DIL switches to watch. See the service manual for your Studer or Revox . Your tape recorder needs to be set up for RS-232 use, otherwise the recorder will not respond. Then there are the settings for baud rate, data bits, stop bits and parity. The script allows you to configure these settings to match the settings of the recorder. The script settings default to 9600,8,1,none.

The computer.

Every decent computer is suitable. As operating system recent versions of Windows, Linux, BSD and OS X will do. Your computer should be equipped with an RS-232 port. If it isn't, you can use a USB-to-RS232 adapter. I used one I got from Conrad, a LogiLink AU0002B. This adapter is based on a Prolific PL2303 chip, it cost about 10 euros.

Furthermore, you need the Perl interpreter and two Perl modules (one for Windows). On most versions of Linux and BSD the Perl interpreter is already installed. Check that from a terminal with perl -v. In addition, you need the Perl modules Term::ReadKey and Device::SerialPort. These may be part of your distribution set or in your ports tree. They can also be found at CPAN.

On OS X, a Perl interpreter may be installed. Check that from within a terminal with perl -v. If it's not installed, Activestate Perl for OS X can be downloaded from the Perl website. For OS X, you need the modules Term::ReadKey en Device::SerialPort too, both are available at CPAN.

On Windows the Perl interpreter will probably not be installed. Check it from within a DOS-box (= cmd.exe) with perl -v. You will find the Perl interpreter for your Windows version at the Perl website. Additionally, you need the perl module Win32::SerialPort (this goes for 64-bits Windows too). Activestate Perl is recommended. It is easy to install and comes with a module manager that allows you to install Win32::SerialPort. In the enormous list of modules you will find it under 'CPAN'.

The cable.

Common serial computer cables (straight or cross) will not work. That's because the Studer pin layout deviates from the norm in the computer world. Hence, you need to make a custom cable. You might use an old computer cable for that, but you will have to solder a new connector to at least one end. The recorders work with RS-232 without hardware flow control, which means that only 3 wires are needed: TX (transmit data), RX (receive data) and mass. The wiring should be like this.

  Tape recorder                                Computer
  9-pin D-type male                            9-pin D-type female 

      +---+                                    +---+
     /  5 |                                    | 1  \
    | 9   |-----------,                        |   6 |---,  
    |   4 |           |           .-------tx---| 2   |   |
    | 8   |----------------.      |            |   7 |   | bridge 4-6
    |   3 |           |     '-------------rx---| 3   |   |
    | 7   |           |           |            |   8 |   |
    |   2 |-----------------------'            | 4   |---' 
    | 6   |           |                        |   9 | 
     \  1 |           '-------------------gnd--| 5  / 
      +---+                                    +---+

Pins 2, 8 and 9 on the male connector for the tape recorder must be connected to, respectively, pins 2 (tx), 3 (rx) en 5 (gnd) on the female connector for the computer. In principle, these three wires are enough for serial communications.
Using an older laptop however, it would only work after I bridged pins 4 (dtr) and 6 (dsr) in the computer connector. A driver problem? Any cable shielding can be connected to the metal casings.

The cable can be checked with a loopback test. To this end, pins 2 and 8 of the connector at the tape recorder end must be connected. See the picture at the right. The Perl script will come up with Receiving exactly what was sent. Is a loopback device connected?. That will tell you that the configured comm-port is correct and that the cable is good.

The Perl script.

A configuration file and the script itself. Two versions, one for Linux, Unix and OSX (with LF line endings) and one for Windows (with CR/LF line endings). Right click on the link and choose Save to download the files. Both files can be viewed and edited with any text editor.

Linux, Unix, OS X:

Windows (32 en 64 bits): You can find information on how to use the script here.
 



Last updated 20 februari 2015.