Can anyone tell me a little about these resistors such as type and characteristics.
Regards, Chris.
OP's photo:
I believe those (R1-R8) are Metal-Oxide Varistors (MOV) intended to suppress large voltage transients coming in on the serial interface lines.
https://www.littelfuse.com/~/media/electronics/.../littelfuse_varistor_catalog.pdf.pdf
Given the big chip is a quad UART with FIFO, this is likely a modem board and they are almost certainly MOVs to protect from lightning and other voltage spikes as MrMark suggests.
Which indicates this is not your average consumer-grade interface card by any stretch of the imagination.
You would be correct this is from a particle size analyser interface controller used in the labs I wanted to bin the electronics inside because the enclosures are stainless steel.