[jes5199]

yeah. I worked on the internal banking connection at Square in the old days (~2011) and it was a _nightmare_. like, pre-TCP/IP connectivity that depended on dedicated copper to do teletype in COBOL-style fixed length fields in a cryptic format that was only specified in scans of paper documents. We had to write an adaptor that looked like, you know, REST on one end but then shoveled all of the traffic onto that single upstream connection, and then had to try to map responses that came back out of order to the right client. Miserable stuff and a threading nightmare.