That is a Digital-VT100 terminal.
The DEC-VT100 terminal was one of a series of VT-NNN terminals which were connected via asynchronous serial (RS-232) that had 4-8 wires (and often used hardware flow control RTS+CTS, DSR+DTR, plus carrier DCD, data transfer RX, TX, SD signal ground). The terminal would be connected to an async/serial card which would often have 4-16 serial ports. The transmit rate for terminals was often 9600 bps, but ranged from 300,1200,2400,4800,9600,19200,38400, and modems ranged from 300,1200,2400,9600,14400,19200,28800 (modems used baud, while terminals used bps/bits per second, and interesting read on the difference).
There were terminal manufacturers that made terminals which emulated the VT-100/102 terminal protocol. The Wyse-50/60 had excellent emulation, and had two serial ports for two! sessions. But the real deal was the NCD-XStation I used to dial-in to the Stratus (VOS) and Sun workstation, run VT-102 emulation and X (yes, over 9600 dialup). That was pre-internet. And yes, I have hacked termcap/terminfo entries.
The DEC VAX-11 and PDP-11 were typical minicomputers, but there were a plethora of minicomputer manufacturers, including Data General (read the book 'Soul of a New Machine' about the DG Eclipse 32bit system), Hewlett-Packard, NCR, Tandem (fault tolerant computers), even AT&T had the 3B2 and 3B1 (I had a 3B1 running Unix, and one of the first Unix systems I used was a Fortune 32:16). My wife programmed the Data General Nova and Eclipse. Although the PDP-11 was prototypical for an early minicomputer, there were many manufacturers, and wide proliferation of terminals, each having their own encodings for special bytes to control cursor movement and behaviors, in addition to the character sets to be displayed. Even the early IBM-PC had ANSI.sys which enabled terminal control characters to use specific sequences to encode movement, position, and color.
The PDP-11 was a very popular system, and helped to cultivate and spread the popularity of Unix. Even the ^S and ^Q key combinations recognized by your xterm terminal program for flow-control date from that era when software flow control competed with the hardware flow control provided by the soft (RTS+CTS) and hard (DSR+DTR) flow control pins offered by RS-232. The 12-bit words on the PDP-11^H^H8 (corrected: DEC's previous PDP-8 and PDP-9 had 12- and 18-bit words, respectively), affected unix and linux (look at the od/octal dump program, and the file permissions bits). The screen program and the job control commands (&,bg,fg,^Z,^C) all descend from that era. While you are looking at early hardware, look at the Hayes modem command set to help you understand how computers communicated remotely. Read about 25-pin male and female serial connectors, 9-pin serial connectors, and realize how far the industry has progressed. Want Nightmares? Read about X-25.
Run a PDP-11/40 in your browser? https://programmer209.wordpress.com/2011/08/03/the-pdp-11-assembly-language/
Enjoy your trip through history.