At 14:54 05-07-05, Ram Meenakshisundaram wrote: J2 connections are not from the VMEbus but can be described as usually an interface to the outside world. Let's use an example of, say, the MVME147* family of processor boards, in which the P2 connector on the module has connections to SCSI devices, serial ports, Ethernet, etc. And in this case of the example MVME147* board, there will be used a transition module as illustrated on a certain auction site using the number 5786398985 (MVME712/M). Note in the pictures the largest connector on the surface of the '712 board. Its the P2 connections jumpered over from P2 on the '147 board. SCSI terminators are the yellow resistor packs. The 5-pin SCSI connector is on the upper right edge. Except for needing to follow the SCSI termination rules, no other terminators are used on this board. The MVME320 is an MFM disk I/F module which, IIRC, has the disk cable connections out the P2 conn in addition to the ribbon cable connectors on the front panel. My '320 is buried in the collection at the moment, but I'm rather sure it too does not have terminators for the MFM disk cables. Cable lengths should be kept short as possible. So, all this rambling is to say that terminations, such as used on the VMEbus, are not *normally* needed on P2. Just depends on what is hung off the P2. Even on a short-length VMEbus, signal "ringing", or reflections, can occur with the short pulse lengths and fast rise-times that may be found on the bus signals. Transmission line theory is involved here. What does P2 connect to on your transputer boards? Regards, Chris F. NNNN Christian Fandt, Electronic/Electrical Historian Jamestown, NY USA cfandt at netsync.net Member of Antique Wireless Association URL: http://www.antiquewireless.org/