CM700 DHCP Configuration

> Is it possible to configure DHCP on the CM700 cable modem?

   No.  Typically, DHCP is a router function, not a modem function.

> I have a number of static assigned IP addresses for printers and
> access points. [...]

   Where "static" means that you configured the address on the device
itself?  What are these static addresses?

> [...] I think the CM700 is assigning DHCP addresses on that conflict
> with the static IP addresses. [...]

   I doubt that the CM700 is assigning anything related to DHCP, because
it's only a modem, and lacks a DHCP server.

> I've tried logging into the modem at 192.168.100.1, but the
> configuration options don't include DHCP.

   I can believe/explain that. (No DHCP server there.)

> My router is a Ubiquiti USG.

   That would explain why any (Netgear) "routerlogin" name would not
work with it as it would with a Netgear router.

> I had thought that my router was doing the DHCP job, [...]

   That would be usual.

> [...] but then noticed today that DHCP was turned off on the router.

   Do you have devices which are using DCHP to get their IP parameters?
If so, then that would suggest that you have a DHCP server running
somewhere.  (And not on the CM700.)

> [...] After I did that, all 3 of my wireless access points (which have
> static IP addresses) went down. [...]

   Showing the actual addresses of these things would be more helpful
than merely claiming that they exist.

> [...] I would like to turn off DHCP on the cable modem, or reserve a
> range of IP addresses for my statically assigned equipment, but I
> haven't found a way to do that.

   If the CM700 had a DHCP server, then you might be able to fiddle with
it, but it hasn't one.

   If DHCP was working when it was disabled on your router, then that
would suggest that you have a DHCP server running on something else (but
not on the CM700, which isn't even connected to the LAN side of your
router).

   It sounds as if you have a rather complicated LAN, possibly a tangled
one.  It might pay to start with some simple arrangement (modem, router,
computer), and get that to work properly, and then start adding
equipment and complexity.  (Until you break it.)