MCT Serial board mystery - Can you crack the pinout code?

[Tothwolf]

On Sat, 15 Nov 2014, tony duell wrote:

>> It sounds like you've just about got it figured out though. If you have 
>> the datasheet for the 1458 (aren't there 1459s on the board too?) then 
>> you can follow the signals through the level converters back to the 
>> UART, and its datasheet should then tell you exactly which signals are 
>> which.
>
> Are you not thinking of the 1488 and 1489 (commonly used RS232 driver 
> and receiver chips)? The 1458 is a dual op-amp.
>
> Op amps were often used as level shifters in older RS232 devices. I 
> guess that's what is happening here.

Yup, I was thinking 1488 and 1489. I guess there wouldn't be a 1489 on 
there if they were using a 1458 as a level converter.