<html><head><meta http-equiv="content-type" content="text/html; charset=UTF-8"/></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">Hello all,<div><br/></div><div><font color="#000000"><span style="caret-color: rgb(0, 0, 0);">What teleprinter models were used at Bell Labs, particularly by the Unix groups? Judging by troff escape sequences, it expected a Teletype Model 37, and early all-caps support implies Model 33 usage. But I don’t have a sense of what users and the core developers used.</span></font></div><div><br/></div><div>I am working on building a Teletype Model 37 ASR emulator for my PiDP-11 with the goal of replicating the early Unix experience as accurately as possible without physical hardware.</div><div><br/></div><div>As I get deeper into research, I’ve learned of a variety of configuration options beyond what the operator could configure with buttons, e.g., sub-models which come with different components, optional components which can be installed later, and features that can be configured by a craftsman. Here are some examples:</div><div><br/></div><div>- Two-color was optional</div><div>- The shift-out character set was configurable</div><div>- An ASR could come without a tape reader/puncher</div><div>- Half-line forward and reverse was optional</div><div>- Character sizes varied, e.g., 72 chars per line at 10 chars per inch, adjustable up to 80 per line; or 86 per line at 12 per inch</div><div>- The paper could be roll paper (friction feed)<span style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0);"> </span><span style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0);">or flat-folded, form-feed paper with marginal perforations (sprocket feed)</span></div><div><span style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0);">- Paper sizes varied, e.g., 3 to 8-1/2 wide or, for sprocket feed, up to 11 inches long and 9-1/2 wide</span></div><div><font color="#000000"><span style="caret-color: rgb(0, 0, 0);">- Some printed control characters; most didn’t</span></font></div><div><span style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0);">- Holding a key could be configured to repeat the character</span></div><div><font color="#000000"><span style="caret-color: rgb(0, 0, 0);">- They could operate </span></font><span style="color: rgb(0, 0, 0);">half-duplex (transmitted data is copied by the sender) or full-duplex (only received data is copied)</span></div><div><span style="color: rgb(0, 0, 0);">- They could receive and transmit at various speeds </span></div><div><div><br/></div></div><div>That’s a lot of options and it’s not exhaustive.</div><div><br/></div><div>The Model 37 product catalog[0] has tables of many configurations and their catalog numbers. Is there a list of the teleprinters purchased by Bell Labs? With that, I could possibly narrow it down like how Warner Losh identified the PDP-7 model used for Unix V0.</div><div><br/></div><div>Thanks!</div><div>Thalia Archibald</div><div><br/></div><div>[0]: https://ia800702.us.archive.org/32/items/TNM_Model_37_terminal_product_catalog_-_Teletype__20170923_0036/TNM_Model_37_terminal_product_catalog_-_Teletype__20170923_0036.pdf</div><div>[1]: https://bsdimp.blogspot.com/2019/07/the-pdp-7-where-unix-began.html</div></body></html>