Annex-M is the new feature included in the BIPAC 7404VGPM ADSL2+ modem/router, which follows the BIPAC 7404VGP in Billion's product line-up. Annex-M, if supported by ISPs, will allow for upload speeds to be increased from the current 1Mbps available with most ADSL2+ plans (which is also known as Annex-A), to 3.5Mbps. Internode is currently the only ISP in Australia to offer this type of upload speed with its Extreme ADSL2+ SOHO and business connections. If you're currently on one of those plans and want to take advantage of the extra upload speed for your business, give the BIPAC 7404VGPM a go. Even if you're not with Internode and can't take advantage of Annex-M, but you're in the market for an ADSL2+ modem/router for the office or home, this one offers plenty of features for your hard-earned cash.

While it is primarily an ADSL2+ modem, it also has built into it an 802.11a/b/g wireless router, a DHCP server, a firewall, a dual-port ATA (analog telephone attachment) for VoIP (Voice Over IP) and a wired router (4-ports). It also has configurable QoS (quality of service) and Firewall management options that more experienced users can sink their teeth into.

As with all Ethernet-based modem/routers, once it's plugged in, it will assign your computer an IP address using its DHCP server and you can log into it using your Web browser to manipulate its settings. However, we did notice some intermittent problems with the DHCP server, whereby it could sometimes not assign an IP address to the only machine on our network until we turned the modem/router off and then turned it on again.

We had no problems using the modem/router with the DHCP server off and by manually assigning an IP to our machine, but for our tests we did use the DHCP server. Once our PC was given an IP address, we logged in to the modem/router to find a clean administration interface with plenty of features to play with. However, while the administration screen was well designed it was a little slow to respond to our clicks. Nonetheless, we entered our iiNet ADSL2 account details and were online in a few seconds.

The modem achieved a sustained download throughput of 18Mbps (2.25MBps), which is excellent, and Internet connectivity was never disrupted, nor slowed, throughout the period of our testing. We also tested the modem on a modest 512Kbps ADSL1 connection, where a sustained download throughput of 392Kbps (49KBps) was achieved. Throughput was observed by using a freely available bandwidth monitor (Bandwidth Monitor 2 by Rokario Software) and our tests were comprised of concurrent file downloads from multiple locations (Microsoft's Web site, NVIDIA's Web site, ATI's Web site and iiNet's FTP site) so that we could maximise the potential of our connection.

Note that the speeds you get on your own ADSL2+ line will vary depending on the condition of the line and also its length. The further you are from your telephone exchange, the harder it will be to connect at a fast speed.

The 4-port switch on the rear of the modem allows connection of up to four computers or other network devices, such as printers or network hard drives, while its wireless access point will let you surf the Web from afar. It also lets you stream video content to multiple PCs in your home, as long as the distances aren't too great and the walls aren't too thick.

While wireless performance in your environment will vary, in our office tests we managed to get a usable Internet connection up to 30m away through glass, plaster board and concrete barriers. Streaming Internet video at this distance was not successful, but we could view Web pages with multiple graphics quite easily. In a home environment, we were able to stream many hours of DivX videos through two double-brick walls within a radius of 10m, which satisfied our expectations of the device. Playback became a little choppy once we ventured beyond 20m away from the router. Again, the streaming performance will vary depending on your environment, but compared to other routers with similar single antenna configurations, this result is pleasing.

Security for wireless networks can be enabled using WEP, WPA or WPA2 encryption (we used WPA for our tests), and a firewall is also built in to the router. You can either use the predefined low, medium or high protection settings, or you can use the predefined packet filters, which give you more specific control over the traffic flow to and from the Internet.

URL keyword filters are also supported. Sites are only blocked if the word you have specified is in the actual URL. This didn't work straight away. We had to apply the settings and then restart the modem/router before the settings would take effect.

The dual ATA ports on this unit allow you to connect up to two analog phones and in the Web configuration page, you can configure two separate VoIP accounts. We punched in the details for our MyNetFone account and the account was registered with the server as soon as we applied the settings.

Voice quality using our ADSL2+ account was clear and the ends of words were not chopped during our conversations, although one recipient did complain about some intermittent 'ticking' noises during a call.

For bandwidth optimisation, the modem has a comprehensive QoS section, where you can define the type of service (Premium, Gold, Silver, Bronze, Best Effort), or manually set the data rate limit. During VoIP tests that were conducted while we were uploading data to the Web, we didn't notice any degradation in voice quality at all. We observed the same voice quality using Premium and Bronze settings. The Premium setting is selected by default.