HO720 / HO820 / HO870: Linux assistance (ID #646)

Basically, HAMEG don't offer Linux support. All data without guarantee (hints of HAMEG customers)!

The actual Linux kernel (from version 2.6.31) supports the interfaces HO820 and HO870 directly, when the module ftdi_sio is activated. Then, the kernel creates with /dev/ttyUSBx a device, which can be addressed like a serial port (/dev/ttySx).

Support for the HO720 can be implemented very easily. Only the files in the source code of the kernel drivers/usb/serial/ftdi_sio.c and drivers/usb/serial/ftdi_sio_ids.h have to be supplemented by one line.

In ftdi_sio_ids.h just below the line

# define HAMEG_HO870_PID 0xed71

the line

# define HAMEG_HO720_PID 0xed72

will be write. 0xed72 describes the ProductId. Accordingly, HAMEG_HO720_PID is copied into the row with the entry ftdi_sio.c. You have to modify the line that now the following line is also located in the file:

{ USB_DEVICE(FTDI_VID, HAMEG_HO720_PID) },

After compiling the kernel resp. the modules the kernel supports the Hameg devices with HO720 interface directly.

The USB port can be addressed as an RS-232 interface by the host software. Created programs for the use of the RS-232 interface can be used 1:1. Only the name of the device has to change from ttySx to ttyUSBx (x is a serial number which is assigned by the kernel).