Are these the 1000 character per second model or the 300 character per second model? I presume they are the slower 300 cps units as the 1000 cps Elliott version on my ICT 1301 needs a powered tape un- roller to feed it. It can still stop between characters even at that speed, but I understand from my old boss when I worked at Elliott's Rochester works that the older Elliott readers did not have the stop on character facility, so that our software always put four null characters after every carriage return line feed pair, and the reading software would always read a line of input at full speed before doing any heavy processing which might take longer than a character time. They are the acoustic cases for Teletype BRPE paper tape punches. 100 characters per second. You had to raise the cover to load new rolls of tape into the unit, then press the feed button on top of the unit as you pulled on the tape until it started feeding itself. Then you closed the cover and when it was ready the computer started punching and the tape fed out of the chrome lined hole on the left hand side. It looks like it fed into the two holes in the desk to the left of these units. My ICT 1301 has had one of these grafted onto it in the 1970s using a Vero board full of TTL logic which is housed within the paper tape reader cabinet. Interest interface between the plus 5 volt logic levels of TTL and the minus 6.3 volt logic levels of the discrete germanium transistor logic of the 1301. A slight cheat - the TTL ground is actually at -5 volts and the TTL's VCC is connected to the 1301's 0 volt earth level. This also means a TTL '1' is a 1301 '0' and vice-versa. The 1301 to TTL signals work fine with no special circuitry, but the TTL to 1301 need a transistor (GET872) to work correctly.