basic airport network configuration

or do i simply connect the modem to Gen 4 Time Capsule's WAN port (with its wireless off) and connect the all three devices by their LAN Ethernet ports and set up the 'ac' wireless on one of the faster 'ac' devices

You will want to use your Gen4 as your "main" router. That is, it should be configured for DHCP and NAT, but disable its wireless radios. Connect an Ethernet cable between the modem and the WAN port on the Gen4.

Connect additional Ethernet cables from the Gen4's LAN ports to each of the WAN ports on the other base stations. Configure each of these other base stations as bridges, i.e., Off (Bridge Mode) so that they get their NAT & DHCP services from the main base station.

Finally, be sure that each of these other base stations are configured to broadcast a wireless network (Create a wireless network), but use the same Network Name, security type and password on each. This will be the foundation for a "roaming" type network.

ATT service coaxial cable plugs into surfboard modem

The "Surfboard" brand of modems......unless something has changed very recently.......are all "cable" type modems, assuming that your provider is furnishing a traditional cable type connection.

Every ATT hookup that I've ever seen is either an older DSL type connection or a newer fiber optic type of connection. You would not normally use a Surfboard cable type of modem with these types of connections.

Can you provide a bit more information.......if ATT is no longer your provider.......about the type Internet connection service that you now have? What is the exact model number of your cable modem?

5268AC xDSL Voice Gateway | ARRIShttps://www.arris.com/products/5268ac-xdsl-voice-gateway/ is a "gateway".......a device that is both a modem and router in one physical package.

That being the case, you cannot run the Gen 4 TC as your "main" router since the Pace gateway will be handling the routing tasks for the network. You will need to run the Time Capsule(s) and AirPorts in what is known as Bridge Mode to allow the ATT gateway to operate correctly.

If the Gen 4 Time Capsule must be located close to the ATT gateway, there is no problem with this type of setup as long as you connect an Ethernet cable from one of the LAN <--> Ethernet ports on the Pace gateway to the WAN "O" port on the 4th Gen Time Capsule.

If you do not want or need the WiFi service from the 4th Gen Time Capsule, it will be an easy task to simply turn off the WiFi function on the 4th Gen Time Capsule so it will function as a wired hard drive.

While you could connect the other Time Capsule and AirPort Extreme to the LAN <--> Ethernet ports on the 4th Gen Time Capsule, it would be better wiring practice to connect the other Time Capsule and AirPort Extreme directly to the PACE gateway instead of the 4th Gen Time Capsule.

Reason.......let's say that the 4th Gen Time Capsule is having a problem......(As a 5+ year old device it will, probably sooner rather than later). If the 4th Gen Time Capsule is not working correctly, then neither will the other Time Capsule and AirPort Extreme be working correctly either if they are connected directly to the 4th Gen Time Capsule.

And, troubleshooting the problem will be difficult, since none of the Apple devices will be working, you won't know which device is really acting up or where to start the troubleshooting process without a tedious trial and error process.

If you connect the other Time Capsule and AirPort Extreme directly to the PACE gateway using the Ethernet cabling, if the 4th Gen Time Capsule is having problems, the other Time Capsule and AirPort Extreme will continue to operate correctly......because they are connected directly to the PACE gateway. Make sense?

i turn off the wireless OFF on the Pac Place gateway

I did not say to turn off the WiFi on the gateway, since you told us originally that you were going to turn off the WiFi on the 4th Gen Time Capsule......but you could do this if you want the 4th Gen Time Capsule to provide your WiFi service and not the gateway. Here I am assuming that the gateway and 4th Gen Time Capsule will be located in close proximity to each other.

If the Pace will be providing a WiFi network that uses a different name and password than the AirPort devices, you can probably leave the WiFi turned on at the gateway if you want to use the Pace for something like a guest network. If you don't need another network though, things will be simpler if you turn off the WiFi on the Pace gateway.

i run separate Ethernet cables out of the Pac Place's LAN <--> Ethernet ports

Correct. Separate Ethernet cable for each Apple AirPort device......or......if it is easier, you could run one Ethernet cable from the gateway to an Ethernet switch, then run separate Ethernet cables from the switch to each Apple AirPort device.

i connect one of the Pac Place's Ethernet cables to each Apple Time Capsule or Airport Extreme in its WAN "0" port

Correct

i create identical Apple wireless networks in Bridge Mode on the Time Capsule and Airport Extreme

Correct. In addition, you would do the same thing if you decide to use the WiFi on the 4th Gen Time Capsule.

do i configure the Apple wireless in DHCP and NAT (pls keep in mind i'm keeping the Pac Place modem/router in place with its wireless off)

None of the Apple devices will use the DHCP and NAT setting since the Pace gateway is already providing DHCP and NAT service since it is the "main" router on your network.

If you do try to set up DHCP and NAT on any of the AirPorts, then you will have two devices both trying to handle DHCP and NAT on the same network. That is a sure recipe for IP address conflicts and chaos as well as another additional issue known as a Double NAT error.

In addition, AirPort Utility will tell you that you should be using Bridge Mode on the AirPort(s)....for good reason.

The only time that you would use the DHCP and NAT setting on your "main" Apple router would be a situation where you have a simple modem (the kind with only one Ethernet port that is not also a router). Your Pace device is a modem/router, which is also known as a gateway.

i thought the Pac Place wireless was incompatible with Apple wireless

This is not usually the case. You would not want to have both the PACE gateway and the 4th Gen Time Capsule producing a WiFi network with the same name and password if they will be located in close proximity to each other.

If the Pace will be providing a WiFi network with a different name and password, then there are usually no issues with running two WiFi networks if you need two networks. If you don't need the second network for "guests", then things will be simpler with only one WiFi network.

in any case i want the Apple wireless on my home network

If the Pace gateway is not going to be providing a WiFi network, then the only WiFi network that you will have will be provided by the Apple AirPorts......so it will be by default your "main" (and only) WiFi network.

i'm hoping to find the off switch on the Pac Pace gateway IP login and turn its wireless off

Look for the "default" IP address of the Pace gateway on the back or bottom of the device. It is usually something like 192.168.1.254 for example only. You will also likely need to enter the default password, which might be something as simple as "password". Contact ATT Support if you need some assistance with the process.

It would be a good idea to first get the Apple WiFi network up and running before you turn off the WiFi on the Pace gateway.

THANKS FOR ALL THE HELP AS I FIGURE OUT HOW TO MAKE IT WORK

We are happy to help. Post back if you need a few tips or even a step-by-step guide to set things up.