You have just one Bus Device per Branch? If so then JP2 – JP5 should have a terminating Jumper and each device should have a terminating Jumper. If this is the only home run from the M1 to the M1DBHR then you should have JP3 on the M1 terminated and JP1 on the M1DBHR terminated. With the M1 powered off measure the resistance across Data A and Data B at the M1 and across each Branch on the M1DBHR — you should measure ~60-70Ω Ohms of resistance.