On the 9-pin D-type of a PC's RS-232 port, the signals are
1 DCD in data carrier detect
2 RXD in received data
3 TXD out transmitted data
4 DTR out data terminal ready
5 GND =
6 DSR in data set ready
7 RTS out request to send
8 CTS in clear to send
9 RNG in ring indicator
By joining 1, 6, 7, 8 they are telling you to connect ...
Looking at the ICL3232 datasheet we see:-
Maximum Data Rate RL = 3kΩ, CL = 1000pF, min 250 typ 500 kbps
and in the SN75C3232 datasheet:-
Maximum data rate RL = 3 kΩ CL = 1000 pF min 250 kbit/s
So it seems there isn't much difference between them.
The SN75C3232 also specifies a minimum of 1000 Kbps with a supply voltage of 4.5 to 5.5 V, so if you ...
Both are USB UART cables, but you need one with 3.3V TTL voltage levels, the microcontroller cannot tolerate RS232 voltage levels and they have inverted polarity as well, so RS232 cables would be incompatible and may break the MCU with overvoltage.