Siemens Gigaset S450 IP

  • Editors' rating
    6.8 Good


  • Dual mode (VoIP and fixed line)
  • Supports up to four VoIP numbers
  • E-mail notification
  • Loads contacts from Outlook (PC)
  • Supports key IM systems
  • Virus protection
  • CLIP function displays caller’s name
  • SMS
  • Phonebook


  • Small display
  • OSD could be improved
  • No MWI
  • Not Skype compatible

The Gigaset S450 IP is the first handset in Siemens’ initial series of DECT cordless phones with integrated VoIP functionality. Traditional in terms of design, this handset has one clever trick up its sleeve: it has connections for both fixed (10/100Mbps) LANs and can be used as a conventional phone, allowing those without a PC to enjoy the benefits of low-cost internet telephony, easily and conveniently. Unfortunately it also has one major drawback — it can’t be used with Skype.

Voice over IP (VoIP) is on the rise, both in the office and in tech-savvy homes. Siemens has designed its Gigaset products to offer the same ease of use and cordless convenience as a traditional landline phone, making it easy for regular users to take advantage of internet telephony and the cost benefits it offers. Considerable costs can be saved, for instance, when making international calls as many VoIP providers’ networks don’t charge for these. And best of all, a PC is not required for internet calls. You can also call worldwide to any other VoIP phone free of charge.

Configuring the Gigaset S450 IP is a little more complicated. Unlike a regular handset that simply connects to your phone socket, the Gigaset S450 IP must be connected to a router via a LAN connection and a phone line. You then have to input your ISP's details using the Gigaset handset's menu, which will probably have you hunting out the relevant documentation. Settings are then automatically retrieved online and loaded onto the phone. Thankfully, providers that use SIP (Session Initiation Protocol) are supported.

SIP is a request-response protocol used for establishing sessions in an IP network. It closely resembles two other internet protocols, HTTP and SMTP (the protocols that power the web and email). A session could be a simple two-way telephone call or it could be a collaborative multimedia conference session. The ability to establish these sessions means that a host of innovative services become possible, such as voice-enriched e-commerce, web page click-to-dial, instant messaging with buddy lists and IP Centrex services. Over the last couple of years, the VoIP community has adopted SIP as its protocol of choice for signalling. However, SIP is still evolving and being extended as the technology matures and SIP products become established in the marketplace.

In operation, the Gigaset C450 IP is no different from Siemens’ conventional Gigaset cordless phones. In addition to an illuminated colour display and keypad with graphical menus, the cordless handset allows you to send SMSs of up to 160 characters and has a built-in phonebook that holds 100 names and numbers. Other features include hands-free calling, headset connection, call forwarding, redial and callback — as well as the ability to setup three-way conference calls.

The Gigaset S450 IP has a reasonable 6-line colour display, but at just 128 by 128 pixels it can sometimes be difficult to see details of incoming emails such as 'subject' and'sender' information, making reading and keeping an eye on new messages more uncomfortable than checking your PC. It also comes with advanced messaging functionality, allowing you to access contact lists and send and receive instant messages via the handset. The Gigaset S450 IP has five volume levels that can be easily adjusted, and a standard headphone socket for connecting a mono headset.

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Furthermore, if the green handset button is pressed for a longer time, the phone switches between the internet and the fixed network. As a result, you can enjoy the benefits of VoIP telephony without having to give up your conventional fixed network connection. The separation of the base station from the battery charging station means the handset can be placed anywhere in the office. The base station can be used with up to six handsets (Gigaset C45), which cost around £49.99 (ex. VAT) each.

The Gigaset C450 IP is a good VoIP phone. It’s not the most stylish, nor is the menu system the most intuitive, but it is robust, audio quality is excellent and it boasts a practical range of features. Installation is relatively quick and painless (if you’re used to configuring VoIP) and firmware upgrades are easily applied.

There are some big drawbacks though. Mainly, there’s no Message Waiting Indication (MWI). Plus, the 15-character CLI name limit replaces the name with ‘unknown’ if it's greater than 15 characters. In tests, we also found that the handset disconnects and re-registers every three minutes, which is very annoying if you’re on a call. Another thing to note is that it treats a number that ends in a star as a number to go out over the POTS line, rather than the VoIP connection, so if you have any 'star codes' in your dialplan that end with a star, then they won't work. Finally, the lack of Skype compatibility is frankly ludicrous.