Modem use

Hi All,
I am new to using Win10, and I would like to find out if Windows 10 will utilize an internal modem? I have an Asus laptop, it does NOT have an internal modem, nor could I find a place for it when it was running Win8.1. I would like to know this before I upgrade my desktop to Win10 because it is currently running Win7.
Any thoughts on what I can/ should do?
Also, I have an external modem that I was thinking about connecting to my Asus, but the external modem only has a 9 pin serial plug. Can I use that and 9 pin to Cat 5 cable adapter to connect to the ethernet jack on my Asus?

Hi,

but the external modem only has a 9 pin serial plug. Can I use that and 9 pin to Cat 5 cable adapter to connect to the ethernet jack on my Asus?

Yes.

Cheers,

FYI: I can confirm that the ZOOM3095 USB dial-up modem works on Win10.

2 others failed for me (TRM561U and Hiro50113).

The instructions were very precise, tho a bit out-of-date; it only
had Win8, but, on the box, it had Win10, which is why I tried it.

A bit more expensive, but worth it. Very clean install. Works just
like my TRM561U on Win7 (in fact, drivers from the same company; for
TRM561U it said 'FAILURE' w/o any reason, but for this ZOOM3095, it
said 'SUCCESS'). The former connected, but couldn't logon. The
ZOOM3095 did so, and I was able to xmit/recv data correctly.