The Traveller Ansible (= FTL Comms)

[whartung]

also keep in mind that, by using toggles or escape sequences one can extend the character set dynamically without expanding the bit depth.

Any modern low bit rate stream would likely be using a modern compression alogrithm.

Many modems used compression to speed up their transfers.

I used to use a 110 baud teleprinter back in college to print out english papers. It had the best printing quality, but the terminal was far enough away from the main lab that 110 was the only thing they could use reliably.

I've done work on a 300 buad acoustic teleprinter as well.

For me, 1200 baud was pretty usable, especially for the type of work we were doing at the time. 300 baud was never really "comfortable". 1200 baud is almost reading speed. 2400 baud was just about perfect.

 

[aramis]

Any modern low bit rate stream would likely be using a modern compression alogrithm.

Many modems used compression to speed up their transfers.

I used to use a 110 baud teleprinter back in college to print out english papers. It had the best printing quality, but the terminal was far enough away from the main lab that 110 was the only thing they could use reliably.

I've done work on a 300 buad acoustic teleprinter as well.

For me, 1200 baud was pretty usable, especially for the type of work we were doing at the time. 300 baud was never really "comfortable". 1200 baud is almost reading speed. 2400 baud was just about perfect.

do you recall the bit pattern? CPS is a much more useful measure, but for a TTT and most VTT , that could be anything from 7-N-0 to 8-E-2/8-O-2
(ranging from 7 b per character to 11 b per character.)

Common baud rates for TTT and VTT

Baud	7 b per character 7n0	8 b per character 7e0 7o0 7n1 8n0	9 b per character 7e1 7o2 7n2 8n1 8e0 8o0	10b per Character 7e2 7o2 8n2 8e1 8o1	11b per characrer 8e2 8o2
110	15.7	13.75	12.2	11	10
300	42.8	37.5	33.333	30	27.272727
1200	171.4	150	133.333	120	109.1
2400	342.8	300	266.666	240	21.818181
4800	685.7	600	533.333	480	436.363636

Note that use of character sets larger than the bitrate will mildly to severely impact CPS.

The code format data_bits-parity-stop_bits. Data is usually either 7 or 8, but 6n0 was used in the early days by some. Using dashes was originally de rigeur, but by the time I started using modems, most BBSs were dropping them - to shorten the BBS list transfer time.

 

[whartung]

do you recall the bit pattern?

The ubiquitous Zip/GZ/Limple-Ziv-Welch compression algorithm is dictionary based. While the stream is broken up into 8 bit chunks (i.e. byte), it's a bit stream, with the most common string patterns taking the least number of bits.

 

[aramis]

The ubiquitous Zip/GZ/Limple-Ziv-Welch compression algorithm is dictionary based. While the stream is broken up into 8 bit chunks (i.e. byte), it's a bit stream, with the most common string patterns taking the least number of bits.

Irrelevant (mostly) to the comm protocol bit pattern.
Which is what I was asking about.