reviews : solwise 300ata

An informal look at using the Solwise 300 ATA

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Solwise 300ATA Tool Windows

This small utility can be used to monitor your 300ATA's status, download and save it's system log and backup it's config.

Download v1.0.0

Please read the readme file for basic instructions.


Solwise 300ATA


The number of VoIP services around today is ever increasing and consumers have never had so many to choose from. One of the main benefits is low cost – VoIP calls are usually cheaper than many of the rates offered by traditional phone providers and often they are free.

PC based phone calls (using a microphone and headphones or a USB phone) are OK for light usage, but they aren’t quite the same as using a proper (cordless) phone around the house and being tied to the PC can be a pain.


Many VoIP phones exist, but I wanted to use our existing phones – why should we have to buy a new phone, when we are quite happy with the one we have? To keep using the current phone an adaptor is required, typically an Analogue Telephone Adapter (ATA). An ATA connects an ordinary phone to the VoIP service, normally via a router and therefore avoids the need to have a PC on. Routers with built-in VoIP ports are available that do the same thing, but they are mainly appealing to people who want a new router - I have several routers and would like to be able to change routers from time to time.

Then came the decision of which VoIP service to use. At first, I thought of using Skype; the author had previously tried Sipgate and Skype and decided upon Skype because of its popularity (so there would be plenty of documentation and several contacts already using Skype) and competitive pricing.

Unfortunately, it seems that there are no Skype compatible ATAs on the market. There are many Skype compatible phones, but suitable ATAs are unheard of. Perhaps this will change in the future. The author receives free minutes from PlusNet’s VoIP service so I decided to go with them in the mean time. Since PlusNet uses the run-of-the-mill SIP standard, any ATA should do the job and I chose the VoIP-300ATA for £28.11 (inc. VAT) from Solwise. The main reason for choosing Solwise is my past experience with them, which has always been good.

Many ATAs are available from different manufacturers. The Linksys PAP2 is recommended by some, but it costs £35+ (unless bought on eBay) and is often locked to a particular VoIP provider, such as Vonage. The Linksys PAP2s available on eBay are usually unlocked but they also tend to be sourced from Hong Kong – I wasn’t willing to wait for the shipping delay and thought it was easier to follow up technical issues with a more local supplier.

Setting up

The ATA arrived from Solwise very promptly (as usual) in the standard Solwise white-box affair with all the cables you need. Also included with the device was a free BT Plug to RJ11 adaptor (referred to RJP/BTS) which allows you to connect a standard phone to the ATA’s phone port. Installing the ATA is pretty easy if you follow the guide.

The built-in quick setup wizard is fine if your VoIP provider is included in the default list (pulver and sipgate) or doesn’t require many settings to be entered, but for some people it won’t be enough. In my case it wasn’t, as PlusNet specify extra details such as port numbers, which are only available from the more advanced web pages.


PlusNet specific settings

Under Advanced > VOIP > Service Provider
Service Provider

If the image above is unclear, here are the settings in plain text:

Registration Interval (secs) = 3600
Authentication Method = AUTH_MD5
Registrar Address = sip.plus.net
Port = 5060
Proxy Address = sip.plus.net
Port = 5060
OutboundProxy Address = nat.plus.net
Port = 5082

I found the default “Dial Plan String” caused the registration to fail so I deleted it.

STUN can be disabled under Advanced > VOIP > Misc Config

Under Advanced > VOIP > User Profile
User Profile

The “Use Profile” name can be anything you like, in this example it is “Office”. The “Auth User ID” and “User Name” should be the username/number provided by your VoIP provider and likewise with the password. For PlusNet Broadband Phone users, the full 7 digit codes should work in most cases. If not, and your user ID begins with a 4 then you can try dropping the 4 and using the remaining 6 digits.

Incoming calls (on our old phone number) didn’t make our phone ring until I updated the ATA’s firmware to Ver 47.68.2RI-003.

Port Forwards

Since I’m using the ATA behind my router (running the RouterTech.Org firmware), I need to forward some ports to the ATA. I created a rule like this:

Port forward rule

I wasn’t sure which protocol was required so I selected both TCP and UDP. As you can see, the selected ports match those specified on the ATA. Originally, I also forwarded the “Media Base Port” 5000, but I’m not sure this was required. To make the port forwarding process easier, I set a static IP address for the ATA:
see Basic > Configurations > WAN > Static IP Settings > IP Address

Then I created a LAN client on my router, to match the static IP address like so:
LAN clients

Finally, I could then apply the previous forwarding rule to the ATA:
Port Forwarding


While PlusNet’s pricing isn’t bad, our current telephone providers gives free weekend calls. Therefore, it would be more economical to use PlusNet during the week and then revert back to the normal phone service at the weekends.

The ATA does have a timers section, but this turns out to be for setting delays when placing calls etc. In theory, pressing the hash (#) key before dialling a number should direct the call over the PSTN, but this probably only works with a phone that doesn’t buffer key presses (ours does).

Four possible solutions I considered were:

  1. A mechanical switch that would allow me to switch our phone between the two lines. An RJ11 switchbox would fit the bill.
  2. A power-based timer switch for the ATA which switches the ATA on and off.
  3. Toggling the ATA to router connection somehow (a script on the router could toggle port forwards or similar).
  4. Toggling the connection on the ATA from a PC using some custom software.

After weighing up the pros and cons of each, I decided to go with the second option.
Fortunately, one handy feature of the 300ATA is that it will route the telephone to the PSTN if the VoIP connection drops or the power goes (via the Line socket). This suited my situation well as it meant that I could use a digital 7 day timer to automatically switch off the ATA at weekends when standard PSTN calls are cheaper than VoIP calls.

Local area code

Normally when calling someone locally with a conventional PSTN phone, you don’t need to enter the area code. VoIP calls are a little different: unless the VoIP provider gives the user an option to specify their area code (on the VoIP provider’s website, for example) then it is up to the user to find a solution. Storing complete numbers in the phone’s memory is one option, but most ATAs have something called a “Dial Plan” string. The Dial Plan allows the user to specify different dialling rules which can activate built in functions (e.g. call return) or features usually defined by the VoIP provider. Also, on some ATAs, the dial plan can be used to insert the local area code for phone numbers matching the user-defined pattern. An example rule for the Linksys SPA941 would be:


which inserts “020” before any 6-digit number that begins with a digit between 2 and 8.

Unfortunately, the 300ATA doesn’t support the “<” character which Linksys term as the “sub-sequence substitution” character. This means the 300ATA can’t insert numbers and can’t add the area code – at least not with the latest firmware at the time of writing (Ver 47.68.2RI-003).

I asked PlusNet to allow users to specify their local area codes which could then be automatically included (to prevent the need to keep entering the local area code), but they have said that it would be a big job so it won’t happen anytime soon. This is a shame because it can be confusing for non-technical family members and makes other VoIP providers more appealing.

Other features

The 300ATA can act as a router and connect to an Ethernet cable modem. In this arrangement, it has all the usual router elements (DHCP, NAT, port forwarding, DNS, Bridge Filtering, Dynamic DNS etc). Several of the ATA’s features covered in the manual I haven’t deal with in this article. Thanks to Steve from Solwise and the PlusNet forum members who helped me determine how to configure the ATA for PlusNet.


All in all, the Solwise VoIP 300ATA is a very capable device and suited my requirements well. It was easy to set up and the Line socket proved to be valuable.


Value for money


One of the cheapest ATA devices on the market.



Apart from the standard ATA functionality, it can act as a router. Unfortunately the dial plan isn’t as feature rich as some ATAs.

Ease of use


Setting up is just a case of connecting up the ATA and entering the VoIP provider details. Using an additional router requires a little more effort, but this applies to any ATA.The hardest part is finding the precise settings for your VoIP provider.

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