TTL UART and safe to use cable length per application

[Kiriakos GR]

Our world wide web this is full of questions about TTL UART and safe to use cable length.

But the answers from the side of consumers they are unclear. 
This is of why, I searched for clues, from the industrial world.

First example: The FTDI chip maker, for TTL UART at 3V (the weaker TTL signal) they offer non shielded cable up to 1.8 meters length.
Part No: TTL-232R-3V3
Data Rates: 3MBaud
Cable Details: 6 core, 5mm UL2464 24 AWG
USB to UART cable Supports +3.3V UART signals

Second example: The FTDI chip maker, for USB to UART, 3.3V TTL logic level, Raspberry Pi compatible flying leads
Part No: TTL-232R-RPI
Cable Length: 1.0m
I/O Voltage: TTL
Virtual Com Port: Yes


Third example Waveshare (Industrial USB TO 4CH TTL Converter, USB To UART)
SKU:21619 Supplied cables:
USB cable 1.2m length
TTL 4x  20cm its one   



Note: FTDI The cables, which are 1.8m long, can cope with data transfer rates of up to 12 Mbaud
Note: Waveshare Host port with CH343 : USB, Baud-rate: 300-921600bps (1 Mbaud), Transmission distance: ~5m
Note: Waveshare   RS232: Transmission distance: ~15m (max theoretical supported 1 Mbaud)
Note: Waveshare   RS485: Transmission distance: ~1200m
Note: Waveshare   TTL : Maximum Transmission distance: Not specified ..
Note: Part No: FT232RL USB Full Speed to Serial UART IC, Data Rates: 3MBaud | USB Speed: Full Speed (12Mbps) 

Note: WinChipHead (WCH) In applications with higher communication baud rate, it is recommended to enable hardware automatic flow
control.
Full-speed USB is only 12Mbps, considering the protocol overhead and other factors, in practical applications, the serial port should be avoided in a continuous or full-duplex of 3Mbps and above high-speed communication status.
The allowable baud rate error of CH343 UART receiving signal is less than 2%, the baud rate error of UART transmitting signal is less than 1.5%.


To be continued ..