The following information applies to recent KT products the DN9848, DN9340 and DN9344. For older products (DN8000, DN3600 family) please contact the factory. There are two separate ports on the units a front panel (RS-232) port and a rear panel (RS-485) port. The RS-485 port should be used for long cable runs as it is a balanced interface. Note however, that for safety reasons software upgrades can only be applied using the front panel (RS-232) port. To accommodate all the various possibilities on current computers, we support both serial and USB interfaces. Since these interfaces differ in internal operation, there are three possible modes selectable in the software Echo On, Echo Off and KT LBB-485. It is essential to set this correctly for the interface in use. 1. Direct RS-232 Cable connection from an RS-232 serial port (D9 connector), using the grey cable supplied with the device to the front panel port. 2. KK systems USB232 This provides an RS-232 port from a USB laptop. This can then be combined with the grey D9 to MINI-DIN lead supplied with the unit to connect to the front port. 3. B+B Electronics USOTL4 This is a USB-to-485 box, with barrier strip terminals inside the box. The only disadvantage is that you can't use it to reprogram units as it is RS-485 only. However, it is in some ways a more convenient and "roadworthy" package for remote control once the units are re-programmed (either with a different PC or using the KK USB232). Pin connections are: DN9848 XLR Pin 1 = GND DN9848 XLR Pin 2 = RDB (+) DN9848 XLR Pin 3 = RDA (-) Switch positions should be: 1 = ON (TD485) 2 = OFF (Echo on) 3 = ON (2-wire) 4 = ON (2-wire) Use mode "Echo On" in the software program. B+B info at http://www.bb-elec.com/ The solutions outlined above have been tested with current KLARK TEKNIK software on Windows 98, 2000, and XP. Other interfaces may well also work, but these are the ones we have tested. If you wish to use a different interface, or are a manufacturer who would like to supply a unit for evaluation, please contact KLARK TEKNIK Service.