ZyXEL Prestige 630 Setup Guide / Mini Review

This content is being maintained for reference purposes but is not being updated.

The ZyXEL Prestige 643 featured on ADSLguide in 2001 as one of the first ADSL Ethernet routers to be reviewed. The Prestige 630 represents a completely different product, both in terms of its looks and functionality. The modem is ZyXEL's low cost USB solution for home users and is available from a range of UK distributors at competitive prices.

The P630-11 (featured in this review) has an Alcatel chipset, specifically it uses the Alcatel MTK-20152 2-Chip DynaMiTe solution, which consists of the MTC-20154 (AFE) and MTC-20158 (USB Controller). ZyXEL also manufacture a Globespan variant of the P630 (model number P630-41), but the Alcatel chipset is cheaper and helps to bring down the retail price of the modem. Other modems which feature the Globespan chipset include the Fujitsu FDX-310. ZyXEL claim that the Alcatel chipset helps improve reliability in combination with Alcatel DSLAM's used by BT, although this is only theoretical. Remember that you may not be connected to an Alcatel DSLAM (BT also source Fujitsu ones), so don't rely upon this statement!

The DynaMiTe chipset performs ATM and USB processing onboard which means that no CPU cycles are consumed on your PC to maintain the connection. Although my CPU usage did appear to rise slightly when downloading, this is to be expected.

Installation & Setup

As always, it is important that you do not plug the modem into your PC until the drivers have been installed. To begin installation, insert the CD provided and click on "Installation Driver" from the auto-run menu.

BTWholesale based ADSL Network settings -- part 1 (required for most UK ISPs)

The primary task is to specify which type of driver you want to use for your connection. The majority of ISPs in the UK use these settings. If you are not connected to the BTWholesale network (e.g. Kingston services, replace the VCI value with '50').

BTWholesale based ADSL Network settings -- part 2 (required for most UK ISPs)

Set the framing type to "VCMUX / NULL". Once again, this is required for normal ADSL operation in the UK. The modem supports other transports such as PPP over Ethernet (PPPoE) for countries such as the United States. For more information about typical modem settings, see this FAQ question.

Reboot required after driver installation

A reboot is required, after which you can plug in the modem and Windows will install the necessary drivers (chosen previously). As with most USB modems, it does consume a fair amount of power from your PC (around 2.5 Watts). The modem is not externally powered and some users may not be able to run other power hungry devices on the same USB controller (for example - USB powered scanner).

Optimizing TCP window size

The drivers make modifications to the TCP window size (the maximum amount of data which the sender can transmit without a requiring an acknowledgement back). The TCP window helps to improve throughput but must be set correctly for best performance. If your setting is correct, or within tolerance limits, you probably won't see this message.

Connection status and current transfer speeds

The 'Control and Status' window is far more interesting  than the usual flashing lights bundled with most USB modem drivers, however, it does not update frequently enough and hence is fairly useless. If you are downloading a large file, the indicators should move to the correct position after a couple of seconds. Smaller files often escape un-noticed (download completed between two samples).

Advanced / 'Hidden' Features

The drivers feature some fairly extensive hidden features accessible by holding down LEFT SHIFT + LEFT CTRL and clicking on the ZyXEL logo.

Now, how did that appear?

Perhaps the most useful tool is the ability to monitor a wide range of attributes which can be derived from the state of your ADSL line. The 'monitor' tab features an application which does exactly this. Most users will be interested in the 'downstream attenuation' value - which is equivalent to the BT WOOSH test result generated during activation. You'll be able to discover whether your telephone line is deteriorating or not!

ADSL Monitor - Downstream Attenuation (a.k.a the 'woosh test')

As you can see, my downstream attenuation is 46.5dB. The engineer recorded a result of 48dB when installed, so it's fairly accurate.

Bits per Tone graph - perhaps more of a gimmick for most users.

Some of the advanced features can change the modem's software configuration and may cause it to stop working - you have been warned!.


The Prestige 630 offers downstream speeds of up to 8Mbps and upstream rates of up to 832Kbps. Like many USB modems, the P630 will support your ADSL broadband requirements for a considerable time into the future. Drivers for MacOS 8.6, 9.x are in late beta, and MacOS X due to be released mid June. Priced around the £85 mark, the Prestige 630-11 is in line with it's competitors and represents great value for money.

Prices: £85.00 (excluding delivery and VAT) – ZyXEL Prestige 630 series
Places to Buy: See our DSL Hardware FAQ
Specs: http://www.zyxel.co.uk/product/dsl/p630.htm

Jeremy Ainsworth

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.