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Billion Bipac 5100S ADSL modem/router review

The Billion Bipac 5100S is sold in the UK by, and as well as being pocket sized, it is a cheap one port ADSL modem/router. The unit is ideal for people who have just the one computer they want to use with ADSL and prefer the connection stability and security even a simple router can offer. Alternatively it is quite happy being used connected to an Ethernet switch running networks of more than one computer.

The router itself has a built in ADSL modem and NAT functionality, and as of November 2004 retails for £40.89 including VAT. The unit can be used on either a static or dynamic single IP address ADSL account, or the NAT function can be disabled for people who have a block of static IP addresses. The router has UPnP, which is seeing an upsurge in use again now that applications like Bit Torrent support it. Also for home workers, it has support for VPN Passthrough. The firewall relies heavily on the basic functionality of NAT, but you can block a few limited services to increase the security.

What you get for your money

The picture below gives a real idea of the small size of this router, it measures just 18.5cm x 12.7cm x 4.7cm. It comes with an RJ11 lead to connect you to your ADSL micro-filter, and a network cable to connect to a single computer. The Power supply is smaller than the usual power brick, and should fit very well into most power strips; the supply to the router is 9V AC 1Amp.

A short set-up booklet from Billion is included, and the CD includes a full manual covering all the basic and advanced features of the unit. To make life simpler, Solwise include a supplementary sheet with screen shots of the settings for a BT and a Kingston Communications phone line.

The LEDs on the front of the router, are large and bright, with their purpose as follows:

  1. PWR - the router has power
  2. SYS - the router is booted and running
  3. LAN - an active Ethernet connection is connected, flashes to indicate activity
  4. ADSL - lit once the router has synced to the ADSL line
  5. PPP - lit once the router has successfully authenticated the supplied username and password

The rear of the router is pretty simple, with just four features:

  1. RJ11 socket for the ADSL line
  2. RJ45 Ethernet socket
  3. Recessed reset button
  4. Power input socket

One small oddity worth mentioning is that when using a hooded RJ45 cable, the bottom lip of the case can make it hard to unplug the cable. A very minor thing, but be careful when unplugging any network leads to avoid damaging the RJ45 plug or socket. The reset button appears to work two ways, a short press (less than three seconds) just reboots the unit, holding in for around six seconds resets the machine to its factory defaults.

Basic Configuration

The router is configured pretty much like all the others on the market. First connecting an Ethernet cable between your computer and the router, waiting for an IP address to be assigned by DHCP (the default IP range is to, and then accessing the web set-up on the router at It does not matter if your ADSL line is plugged in or not at this stage, you can configure the router in anticipation of your ADSL line being activated, so you can use it as soon as possible after activation.

The screenshot above shows what options you have when you first connect to the router, of course it is password protected, and to get to this point you will have needed to enter admin for the username and admin for the password when prompted. The configuration is fairly simple; just click the Wizard Setup link shown in the screenshot above, to be guided through the options that need changing.

The first step is to check the ISP parameters, which should be set as default to the values above, so click Next to continue to the next step.

The next stage is to enter your ISP assigned username and password. We have shown one of the BT test accounts - the password for this login can be blank, or any old text. If you have a static IP address we still recommend leaving 'Obtain an IP Address Automatically' set on this page, just in case your ISP told you the wrong IP address. Static IP addresses are controlled by the ISPs hardware, which is simply told to keep handing the same IP address out for a specific account name.

It is best to leave the connection setting marked as 'Nailed-Up Connection'. This means no matter how long you leave your connection idle, the router will keep the connection open. If you want, you can switch to letting the router only connect on demand, but this can mean a few seconds delay if it does disconnect when you first request a web page again. The Network Address Translation field should be left at 'SUA Only' for the majority of users. An explanation of the NAT modes is shown below:

Step three in the setup, displays all the settings you have entered, so you can review them and check you have got things correct. For people who want to use the router on a different LAN IP range, which is entirely optional, there is a button to take you to the LAN IP configuration pages.

If all is well, you should see the PPP light come on a short while after pressing the Save Settings button. You can double check the status by looking at the System Status under the Maintenance menu. An example using the bt_test@startup_domain login is shown below:

The show statistics button provides a wealth of other information, and is a pop-up that refreshes every five seconds by default. Unusually it also tells you the CPU load of the router, so if you are using a very busy network you can monitor how busy the routers processor is, as well as the speeds of the ADSL line.

Advanced Configuration

The 5100S is not limited to just getting you online, it does have further options that allow you to configure services to be visible behind the firewall functionality of the router. You may need further configuration, commonly called port forwarding, for some online games, peer to peer applications, and running things like a web server.

Under the NAT menu item for the router is the screen shown below. Normally most people will be using the SUA Only option, and to configure a virtual server you would click the 'Edit Details' link. Selecting None would turn NAT off, which means you would have no connection unless you are provided with a block of static IP addresses. The Full Feature option is what is commonly known as Multi-NAT, where multiple public IP addresses are translated to multiple private LAN IP addresses.

Once you have clicked the 'Edit Details' link, the second screen is shown which lets you see what rules you have configured already, and add additional rules. Eleven rules can be entered, and fortunately with such a small amount available in the web interface, you can specify a port range. For example if you wanted to forward ports 6881 to 6999 to the computer with the LAN IP address of, you would enter 6881 as the Start Port No. and 6999 as the End Port No. and the IP address as Obviously you need to click Save for the settings to be stored. Unlike some other routers, when you save settings on the 5100S, it does not totally reboot the router, it appears to save settings very fast, and with minimal interruption to the other computers on a network.

Rule 1 is slightly different to the others. It would normally be termed as the DMZ option. Entering an IP address for Rule 1 means that all incoming unsolicited traffic would be directed to the computer at that IP address. This can prove useful if you run out of rules, and need to get something like an X-Box or PlayStation 2 online.

The firewall options are very basic, but by their nature therefore very easy to use. You have just six options as shown above, which allow you to block certain types of traffic in an incoming direction.

For those people with a dynamic IP address from their ISP, the inclusion of support for DynDNS is useful, since this allows you to use a domain name to direct people to any services you are running. This avoids the need to keep telling people about your change in IP address.

The router does support UPnP, which is actually turned off by default. Two levels are supported, the first check box will simply let you see the Internet Gateway icon, and observe the statistics, and tell you the router is connected. The second option is the one to select if you want applications like Windows Messenger and Bit Torrent to be able to open and close ports automatically.

There is a command line interface available via telnet, which reveals a number of options including support for SNMP. A very simple and useful command is shown above, which reboots the router for you. The presence of a telnet interface is not critical, but very often there are features in a router only available via the command line interface.


The unit is very small, but this hides what appears to be a very stable little router. It may not have all the features of things like the more expensive Speed Touch 530, but many people have no need for those features. During the course of the review, the router was happy serving content for a web server, and being used for fairly large amounts of web browsing.

Latency wise the unit appears pretty much standard, which is really where most routers are these days. So for gamers there is often little difference between units. The difference is more about reliability during game play, which the 5100S seems to have.

Running some speed tests showed good results, varying around the same average for the ADSL line used for the reviews, averaging at around 940kbps downstream and 252kbps upstream. The diagnostics section of the routers web interface shows the attentuation and other parameters of the ADSL line.


Small but perfectly formed comes to mind. With its size you almost expect it to run off a couple of AA batteries. For people who are looking for a first router, the unit seems ideal as it is cheap and easy to set-up. Additionally, Solwise are very good in providing that extra bit of documentation, and a lot more support than the various PC component box shifters.

The small number of port forwarding rules is a bit of a concern, but with ranges allowed most people should be fine. Having UPnP is useful, as this simplifies issues like port forwarding for novice users, and for those with security concerns, it is easy to disable the UPnP.

The presence of a telnet interface is perhaps a bit beyond your novice router user, but it will give those keen to learn more, something to get their teeth into.

Prices: £34.80 - Billion 5100S (£40.89 including VAT)
Where to Buy: See our DSL Hardware FAQ

Andrew Ferguson

The contents of this review should not be relied upon in making a purchasing decision - You should always discuss your requirements with your service provider and hardware supplier.