If it is a dip switch thing like has been said duplicate the old printers setting if that's not possible you have more work.
print a test page to get serial interface settings (turn off printer hold down feed button and turn printer on)
do that for all your printers to see what is "normal" for your site
Baud rate is often 9600 compare that to the baud rate on other printers
In the past (and this could have changed) all aloha printers had to be set to the same baud rate. Data bits, parity, stop, and handshake could be different but had to agree with the port settings on the port they were hooked to and term and printer baud rates need to agree
Add other information points to your troubleshooting, (assuming you have another terminal in the setup that has an epson receipt printer) my t88iii's are interchangable with my u220b's and all I have to do is pop out the rj45 from the printers adapters to swap them around. YMMV
1)plug receipt printer in where the u220b would be using the u220b cableing, see what happens
2)plug the u220b in place of the reciept printer using the receipt printers cableing, see what happens
good luck printers can be so frustrating