The Linksys PAP2T is one of the most popular analogue telephone adapters (ATAs) ever made, allowing you to connect a standard analogue telephone to a modern VoIP service. Although it’s now a legacy device, it still delivers excellent call quality and is an ideal choice if you already own one.

This guide shows you how to configure a Linksys PAP2T for use with Plexatalk. It should also work for the Linksys PAP2, SPA1001, SPA2100, SPA2102, SPA3000 and SPA3102, as they all use very similar firmware. The Cisco SPA112 also shares many of the same settings, although some menu names and layouts differ slightly.

Before You Start

Important

The Linksys PAP2T is a discontinued product that only supports SIP over UDP. It does not support SIP over TCP or SIP over TLS, meaning it cannot be used with providers that require encrypted SIP signalling. This may be a problem if you can’t disable SIP ALG on your router and have it enabled.

As these devices have been out of production for many years, most available today are used, refurbished or old stock. Unfortunately, counterfeit units also exist, so we recommend purchasing from a reputable supplier.

This guide assumes the adapter has been reset to its factory defaults.

You’ll also need the following information from Plexatalk:

• SIP Server (Proxy)
• SIP Username/User ID/Extension
• SIP Password

Step 1 – Find the IP Address

Before you can configure the PAP2T, you’ll need to access its web interface.

1. Connect an analogue telephone to the Phone 1 port.
2. Lift the handset.
3. Dial:

****

4. Then dial:

110#

5. The PAP2T will read out its IP address.

Make a note of the IP address.

Step 2 – Log into the Web Interface

Open a web browser on a computer connected to the same network as the PAP2T.

Enter the IP address into the address bar, for example:

http://192.168.1.25

If prompted, enter the administrator password.

(Some PAP2T adapters do not have a password configured by default.)

If you see Admin Login in the top-right corner, click it.

Next, click Advanced View.

You should now see additional tabs including SIP, Regional, Line 1 and Line 2.

Step 3 – Configure SIP Settings

Select the SIP tab.

Change the following settings from No to Yes.

While you’re still on this page, locate the codec settings and change the preferred codec from G711u to G711a.

G.711 A-law is the standard codec used across the UK and Europe and provides the best compatibility and call quality with Plexatalk.

Click Save Settings.

Step 4 – Configure UK Regional Settings

The PAP2T defaults to North American telephone tones like the screenshot above. To make it sound like a standard UK telephone line, click the Regional tab and update the following settings.

Call Progress Tones

Miscellaneous

Change the following setting:

Click Save Settings.

Step 5 – Configure Line 1

Click the Line 1 tab.

NAT Settings

Proxy and Registration

Subscriber Information

Further down the page, locate the audio codec settings and change:

Leave all other Line 1 settings at their default values unless instructed otherwise by Plexatalk.

Click Save Settings.

Step 6 – Configure Line 2 (Optional)

If you want to use the second telephone port on the PAP2T, click the Line 2 tab and repeat the same configuration using the credentials for your second Plexatalk extension.

If you only need one telephone, you can leave Line 2 unconfigured.

Step 7 – Reboot the Adapter

Once you’ve finished configuring the PAP2T, disconnect the power for around 10 seconds before reconnecting it.

Within a minute, the Phone 1 LED should illuminate and the adapter should register with the Plexatalk platform.

You can now make a test outbound call and then call the number back to confirm inbound calls are working correctly.

Troubleshooting

The PAP2T won’t register

Check the following:

• The SIP server (Proxy) is entered correctly.
• Your User ID and Password match the credentials supplied by Plexatalk.
• NAT Mapping Enable and NAT Keep Alive Enable are both set to Yes.
• Your router has an active internet connection.

Reboot the adapter after making any configuration changes.

I can’t access the web interface

Dial:

****
110#

again to confirm the IP address hasn’t changed.

Calls have no audio or only one-way audio

Verify that:

• G711a is selected as the preferred codec.
• NAT Mapping Enable is enabled.
• NAT Keep Alive Enable is enabled.
• Turn off SIP-ALG on your router – it may be on and locked down by your ISP, in which case you’ll need a different router or adapter that supports TLS.

Registration fails even though my username and password are correct

If your PAP2T still won’t register after checking your SIP credentials, there are a few additional settings worth checking.

Try using a public DNS server

Some ISP-provided DNS servers can occasionally have difficulty resolving SIP server hostnames quickly or reliably. If you’re using a hostname such as testzp837.voip.plexatalk.co.uk, try configuring a public DNS server on the PAP2T.

Navigate to the System tab and set:

Alternatively, you can use Google’s DNS servers:

Click Save Settings when finished.

Check the Date and Time

An incorrect system clock can also cause unexpected behaviour on some firmware versions.

On the System tab, verify that the time zone is correct and that the adapter is successfully synchronising with an NTP (Network Time Protocol) server.

For UK users, we recommend:

After changing either the DNS or time settings, reboot the PAP2T and allow a minute for it to register.

FAQ – Configure a Linksys PAP2T

Linksys PAP2T – Configuration

Despite being over a decade old, the Linksys PAP2T remains a reliable and capable analogue telephone adapter. With the correct UK regional settings and Plexatalk configuration, it continues to provide excellent voice quality while allowing you to keep using your existing analogue telephones.

If you’re looking for a more modern alternative with ongoing firmware updates and support for SIP over TLS, our team can also recommend newer ATAs and IP phones that work seamlessly with the Plexatalk platform.

The post How to Configure a Linksys PAP2T (PAP2) VoIP Adapter for Plexatalk appeared first on Plexatalk.

In this guide, we’ll show you how to connect Zoiper Desktop to your Plexatalk VoIP service, including how to enter your SIP credentials, choose the correct transport protocol, and complete the account registration. We’ve also included troubleshooting steps to help resolve common issues such as registration failures, network connectivity problems, firewall restrictions, and SIP ALG, making this guide useful whether you’re configuring a Plexatalk account or setting up Zoiper with another SIP-based VoIP provider.

Step 1 – Enter your account credentials

Open Zoiper and choose to add a new account.

Enter the following details:

• User ID and Domain: Format of %userid%@domain – for example 843732@testac.voip.plexatalk.co.uk
• Password: Your SIP password

Once you’ve entered your credentials, click Next.

Step 2 – Confirm the hostname

Zoiper will automatically populate the hostname during the setup process.

If the hostname is correct, simply click Next to continue.

Step 3 – Skip the proxy configuration

When prompted to configure a proxy server, leave the settings unchanged and click Skip.

No proxy configuration is required for Plexatalk.

Step 4 – Select the transport protocol

Choose the transport type that matches your Plexatalk configuration:

• UDP – Recommended for most users.
• TCP – Use if instructed by your administrator.
• TLS – Available in Pro version only. Select this if your service has been configured for secure SIP over TLS.

After selecting the transport type, continue with the setup.

Step 5 – Setup complete

Zoiper will verify your account settings.

If everything has been configured correctly, you’ll see a confirmation screen with a green tick indicating that your account has been successfully added.

Click Finish to complete the setup.

Looking to Download Zoiper or Buy the Pro Version?

Get Zoiper today from their website

Troubleshooting

If your account isn’t registering successfully, work through the following checks before contacting support.

1. Verify your login credentials

The most common cause of registration failures is incorrect account details.

Check that:

• Your Username (or Extension) is entered correctly.
• Your Password matches the one provided by Plexatalk.
• The Hostname / Domain has been entered exactly as supplied.

Even a small typo or an accidental space can prevent registration.

2. Check the transport protocol

Ensure you’ve selected the correct SIP transport method.

Plexatalk supports:

• UDP – Recommended for most installations.
• TCP – Used in some network environments.
• TLS – Available for Zoiper Pro users when secure SIP has been configured.

If you’re unsure which transport to use, start with UDP unless your administrator has advised otherwise.

3. Test network connectivity

If your credentials are correct but registration still fails, confirm your computer can reach the Plexatalk server.

Open a terminal or command prompt and run:

ping your-sip-server.example.com

Replace your-sip-server.example.com with the hostname provided in your Plexatalk account.

Windows

1. Press Windows + R.
2. Type cmd and press Enter.
3. Run the ping command.

macOS

1. Open Terminal (Applications → Utilities → Terminal).
2. Run the ping command.
3. Press Ctrl + C to stop the test.

Linux

1. Open your preferred Terminal.
2. Run the ping command.
3. Press Ctrl + C to stop the test.

If the server responds, your computer can successfully reach the Plexatalk platform. If the request times out or the hostname cannot be resolved, there may be a DNS, firewall, or network connectivity issue.

Note: Some servers intentionally block ICMP (ping) requests for security reasons. A failed ping doesn’t always mean the SIP service is unavailable, but it can be a useful first diagnostic step.

4. Check your firewall and antivirus

Some security software may prevent Zoiper from connecting to external SIP servers.

Temporarily disable your firewall or antivirus (if appropriate) or ensure Zoiper is allowed through the firewall before testing again.

If you’re on a corporate network, your IT department may also have firewall policies that block SIP traffic.

5. Disable SIP ALG

Many home and business routers include a feature called SIP ALG (Application Layer Gateway).

Although it’s designed to help SIP traffic, it often causes registration failures, one-way audio, dropped calls, or intermittent connectivity issues with hosted VoIP services.

If you’re experiencing any of these symptoms, we recommend checking whether SIP ALG is enabled on your router and disabling it if possible.

Read more about SIP ALG here.

6. Try another network

If possible, connect your computer to a different internet connection (for example, a mobile hotspot).

If Zoiper registers successfully on another network, the issue is likely related to your original router, firewall, or ISP configuration rather than your Plexatalk account.

7. Restart Zoiper

After making any changes to your network or account settings, completely close Zoiper and reopen it to ensure it attempts a fresh registration.

Still having problems?

If you’ve completed the steps above and Zoiper still won’t register, please get in touch.

To help us diagnose the issue quickly, include:

• Your extension number or SIP username.
• The hostname you’re connecting to.
• The transport protocol you’ve selected (UDP, TCP, or TLS).
• A screenshot of the Zoiper registration status or any error messages.
• The operating system you’re using (Windows, macOS, or Linux).

Providing this information upfront helps us identify and resolve issues much more quickly.

Frequently Asked Questions

The post Connecting Zoiper Desktop to Plexatalk appeared first on Plexatalk.