TD8E with more than 2 tape transports

Hi folks, as I already mentioned in alt.sys.pdp8 I'm currently experimenting with a TD8E controller in a pdp8/e and more than one TU56. I installed two TU56. The first one has the G888 modules. The second one will be daisy-chained to the first one. Currently I tried only the control cable. Forgot to bring the data cable with me. It looks as I now can access units 0 and 1 on both TU56. I'm quite confident that the data part will work as well. Currently only one or two of the four transport are working properly (The drives are currently being repaired) but there's enough functionality for a proof of concept. The next step will be three modifications: 1. Make the TD8E respond to all four TD8E addresses - This is done easily and non-destructive by pulling the address select jumpers to ground. 2. Add a latch to the TD8E that will hold the two TD8E address bits and feed them through two former ground lines of the cable. 3. Add a demuliplexer to the paddle board. Use the original select signal and the two additional ones to generate 8 select lines. If I'm right I'll have a TD8E that supports up to 8 tape transports (4 TU56). That would be very nice for the beginning. If anybody has already tried this or there's something I've missed, please let me know! Regards, Philipp :-) -- http://www.hachti.de