Tim, and archie are correct you have to provide a little more information.
It is like going to the doctor, my foot hurts..... which one? My foot.
Anyway here we go:.
Wireless router: is 10.10.30.51 ( assume that is your public IP?)
The idea of this router is to map public ip back to your non routable internal ip 192.168.0.xxx (lets call this a private IP)
Having said that all your devices internally should have that 192.168.0.xxx range. Your wireless router is on the edge so that one should do the NAT.
I am going to use some IP address as example. I noticed that you put all on the 10.10.30.*** range that is fine, i stick to the 192.168.0.xxx in my post.
SPA3102
Connect WAN to your Wireless router, this is only needed if your router is doing your network switching aswell. If you have another switch you can hook the SPA to that aswell. The important part is that the WAN port of the SPA is connected to your network.
In the router config:
Connection type: static IP
Static IP: 192.168.0.150
Gateway: the IP of the Wireless router 192.169.0.1 (this is the private IP it should have)
Netmask: 255.255.255.0
Optional settings (actually not really optional).
Primary DNS: the DNS of your ISP
DNS Server order: Manual
DNS Query mode parallel
Primary NTP Server: find one that works for you.
Using this will allow you to see what time the call came in on the SPA in the Status screen, handy with trouble shooting.
PSTN Line:
Line Enable: set to Yes.
SIP Transport UDP
SIP Port 5061 (Make sure you remember that we need it in 3cx)
Proxy and registration.
Proxy: 192.169.0.2 (The IP address of the 3cx server)
Outbound proxy: same as proxy
Subscriber Info: (try this first as it might be the cause of your initial problem).
Display name: IT Farmer

.
User ID: this is the line ID of 3cx guess that will be 10001
Password: the password you entered in 3cx.
Use Auth ID: YES
Auth ID: 10001
Dial plans:
Dial Plan 8: (S0:10001)
PSTN-To-VoIP Gateway Setup
PSTN Caller Default DP: 8
In 3cx under lines, go to the PSTN gateway.
Gateway hostname or IP: 192.168.0.150
Port: 5061
Registration: Both in-out calls
Gateway capabilities: Supports Re-Invite
Location of destination number: To.user' field and Request-line URI field
Other options: Caller ID is in 'user' part of (one of the following): 'From" field
and that should work. Well let me put it this way, archie and myself spend a fair bit of time online to get the caller ID etc working and we believe that this setting is the most succesfull to get it all going.
So let us go how you got.