the terminator needs to be multimode to work with an SE chain as well. if it lets you take off the lid you could check the IC datasheet to see whether it is, this is what i did with mine.

otherwise if you had an LVD-capable SCSI adapter, you could jumper the devices to LVD and see if the termination error is gone. it might be easier and cheaper to get another adapter than to find a compatible terminator actually...

Thanks for the reply. It was easy to get the cover off. The chip is a Texas Instruments UCC561DP.

It doesn't mention SE in the spec sheet. Here's what it says:

Features:
- SCSISPI--2, SPI--3 and SPI--4 LVD SCSI 27-Line, Low-Voltage Differential Regulator - 2.7-Vto 5.25-V Operation
- Integrated Regulator Set for LVD SCSI
- Differential Failsafe Bias

Description:

The UCC561 low-voltage differential (LVD) regulator set is designed to provide the correct references voltages and bias currents for LVD termination resistor networks (475 , 121 , and 475 ). The device also provides a 1.3-V output for “diff sense” signaling. With theproperresistornetwork,theUCC561solutionmeets the common mode bias impedance, differential bias, and termination impedance requirements of SPI--2 (Ultra2), SPI--3 (Ultra3/Ultra160) and SPI--4 (Ultra320). The UCC561 is not intended for SPI--5 applications. This device incorporates into a single monolith, two sink/source reference voltage regulators, a 1.3-V buffered output and protection features. The protection features include thermal shutdown and active current-limiting circuitry. The UCC561 is offered in 16-pin SOIC (DP) package.

Found a cable on tbe bay with the description:

New and unused 1.2m SCSI Ultra2-LVD/SE 4 device + terminator ribbon cable p/n 498583-00 68 pin

Picture of the terminator shows LVD SE on the casing.

Do you reckon that will work. Also could I use 68 pin to 50 pun adapters on the cable for say a CD-RW drive?

Many thanks.

that cable would work, yeah. i've never adapted 68-pin cables to 50-pin but from what i understand it should always work when the terminator is at the cable end. the adapter apparently just blocks the high byte but doesn't terminate it. from what i understand, high byte termination is only needed when you end the chain with the adapted 50-pin device and also use internal termination on that device.

i'm actually not sure why someone would do this in the first place if you could just end with a 68-pin device instead. really, high byte termination with these adapters is mentioned quite a bit in SCSI literature for what seems to be a weird setup. the most practical application i can think of is if you solely wanted to run some 50-pin optical drive but your controller only had a 68-pin connector. but then i would think that setting the bus width to 8-bit should be enough...

the ideal setup though would be to get a 2940u2w or 19160/29160 which allow you to use LVD and SE on the same card, not that you would really notice a difference on such a system of course.

Thanks Auron. Cable ordered, so fingers crossed. The tape drive, being 68-pin would be at the end of the chain, with any 50 pin device sitting before, if I do decide to add a SCSI optical drive.

The cable arrived this afternoon - much quicker thsn I thought. Got the controller and the two drives cabled up tonight. Powered up and success - all devices correctly detected!

Thanks again for your help.