" ... some kind of hardware device which isolates the line and all that." I believe part of the MIDI specification includes explicit decoupling of each device from the network via optical coupling. ( Ref: _MIDI systems and control_, Francis Rumsey ... "The interface incorporates an opto-iso- -lator between the MIDI IN and the device's microprocessor system. This is to assure that there is no direct electrical link between devices ..." ) Anyhow, such a component is commercially - and easily - available. -- richard ===== -- richard childers rchilder@us.oracle.com 1 415 506 2411 oracle data center -- unix systems & network administration Klein flask for rent. Inquire within.