Cordless VoIP handsets... do they exist?

hey there;


Just a side note; you can use ANY cordless phone with VOIP; after you connect the base unit to the Adapter,you can plug it into a cordless phone, either stand alone, or as part of a system, and it will work just fine.
I have tried both 2.4ghz, and 5.8ghz, and they both function normailly.

Adapter?

The adaptor that wase4711 is talking about is a digital to analog phone adaptor.  Devices such as the Cisco ATA 186 or the Motorola VT1005.  Most of the residential VoIP services (Vonage, AT&T, etc) now use these devices and you can buy at least the Motorola at Circuit City and possibly at other consumer electronic stores.  I have two of them (three lines) and use only normal cordless phones with them for voice calls.

So these adapters are what connect your external PSTN lines to your VoIP network.

Hello,

I was just doing a search on the web for VoIP cordless phones and stumbled on this thread.  I'm wondering if I could probe your brains and ask if you guys would value having a cordless VoIP phone over the "telephone adapter" used in conjunction with a regular cordless phone.

Thanks,
Raymond
www.arkonnetworks.com

Well, Raymond, what advantage does your "cordless" phone offer, that my plain old cheap VTEC doesnt provide??

If there are distinct advantages, then I would be interested...

Hello,

I don't have a phone.  I was just throwing the question out there for your input.  Can you think of anything specifically that would be an advantage?  How about if the unit was 802.11?  Or how about if the TA and phone were in one unit for easy of use and less cable clutter?  Would those matter to you?  

Try www.DECT.org

The radio interface is H.323 - plain vanilla, and a SIP interface simple to make. Both base units and terminals comes as PCMCIA cards - which enables you use the technology as wireless LAN - which e.g. both Siemens and RTX have done.

All DECT phones are fully digital, which is why you see handsets from RTX and Siemens - these are DECT phones... plain vanilla - €5 a piece.

To those in the US: Sorry, but you elected in 1992 to not adhere to the ITU radio frequency allocations to allow the US industry to develop a "better" technology. Sometimes life sucks. A variant of DECT is BlueTooth. There are also DECT phones on the 2.4GHz for the US. However, outside the US - DECT has allocated the 1820MHz frequency, except for |920MHz in South America.

>> outside the US - DECT has allocated the 1820MHz frequency

Is that why DECT phones in the uk are not affected by microwave ovens but videosenders are.

I like videosenders. just dont use the microwave :(

DECT has a "protected frequency" that may not be used by other technologies.
Other technologies - such as videosenders, game consoles, WLAN and BlueTooth use the 2.4GHz will interfere with one another.

I don't know the frequency of microwave ovens - but they should not interfere with DECT - or other ITU allocated range - such as the 3G services. If they do, this should be reported to Ofcom - and you are able to return the goods as "deficient" as it interferes with the UK RF allocations. However, you cannot complain about interference on 2.4GHz, 3.4GHz and 5+GHz - these have been declared "free for all" to use a found suited.
I have found "remote sensors" in the UK - e.g. an outside thermometer that was based on "liberated" US frequency and sold in the UK where the same frequency is used by the police.

High-frequency equipment may interfere by inference cause between equipment (pattern of waves are generated in a lower frequency range). This is a difficult topic - but if you suffer this in an allocated part of the spectre, Ofcom should be able to identify a local resource that will track down the cause of the problem. That is why we pay for using the licenced RF range.
Inference is usually simple to shield.
Beware that an RF "inspector" may confiscate your neighbours microwave if this is the culprit.

A simpler explanation:
DECT is based on "Dynamic Channel Selection" (a technology recently patented in the US - but has been around for 10+ years). The handset and base station will listen to all channels/carrier bands and for every packet, it will choose the current "best" channel with best S/N ratio for the next packet.
So if interference or inference is present - it will change to another without your intervention - not even notice anything.

This is why DECT does not require any frequency planning - and you don't have to worry about neighbours using the same frequency. It is made to stay away from one another.

Advantage:
DECT supports SMS - which may be supported on the full H.323 interface - but not SIP.
E.g. Skype could most likely make a bridge from the character / chat interface to DECT SMS, as could someone do with MSN Messenger and similar services - you can remove the 160 character limited on a closed network.
The Messnger messages would then appear in the handset window as an SMS - and allow you to respond with the handset - as SMS.

>> However, you cannot complain about interference on 2.4GHz, 3.4GHz and 5+GHz - these have been declared "free for all" to use a found suited.

Is there any way to remove/supress the interference.

(a) Is correct.
(b)Think Faraday's cage: Radio waves will be on the outside of conductive surface. So all metal objects will halt radio waves - like the steel in concrete. These will also act as "antennas" and atttract waves. As will aluminium walls / dividers. Now the higher the frequency - the more power is required to make the radio waves penetrate. Glass will stop 5GHz, plaster wall the 3.4GHz while a concrete wall is required at the 2.4GHz - at signal levels used.

A microwave oven will emit far more energy. Here the US is better prepared - because the FCC has enforced tougher restrictions. Microwaves sold in Europe are commonly not permitted in the US. You can purchase equipment to measure emission - and stop it. A simple foil of aluminium behind the wall covering will halt emission from a microwave pass through the wall. Just ground it somewhere - e.g. by inserting a pin. Frontal radioation in the room will require some other covering - or that you make twists and bends that obstruct. The door of your fridge may do - or a net that usually goes in front of the fireplace will capture most. Again - ground it - (as the kitchen sink).
See if the store carries microwaves that are certified for use in the US - with an FCC approval.
Other common sources of radiation are satellite dishes. These induce a field in the dish to form inference that enable you to capture the minute signals from the satellites far away.
A final source of low-frequency radiation is high-voltage power line. However, with the energy these carry - and conductive material of some length will act as antenna, and anything that sometime leads and sometimes does not - will be a capacitator. With the right combination of steel girders - and other things - anything can appear.
I have searched for conductive wall paper - that would reduce radiation and radio interference - but not found any in "regular stores" yet. However, you may use isolation "pads" with aluminium to limit radiation e.g. those intended for noise&heat reduction in cars.

We that was interesting to read. I need my videosender to be able to receive the signal from the downstairs transmitter but at the same time block out the microwave oven when it's used. I've also noticed that standing in the transmission path will block the signal.

Thanks,

There is so much "theory" about, that sometime proving things by simple means help to fend off all doubts.

I need my videosender to be able to receive the signal from the downstairs transmitter but at the same time block out the microwave oven when it's used. I've also noticed that standing in the transmission path will block the signal.

"Glass will stop 5GHz, plaster wall the 3.4GHz while a concrete wall is required at the 2.4GHz - at signal levels used."

I'm not sure what you mean by this.  Specifically, "Glass will stop 5GHz."  Are you saying that a 5.8 GHz phone would theoretically, not work if the base unit or the handset was used from within a glass room?  

Consider a meeting room in an office with temporary walls. If you make a WLAN condiguration in the office, those in the meeting room will be able to use the regular 2.4GHz WLAN - as transmitters of .5W. If you change to 3.4GHz, the plaster wall will stop the radio waves - but if the room has a window, you may still use the same WLAN. If you use 5GHz or high - then the radio waves will not penetrate the glass - but bounce off - it is "radar" now.

Other way around: A "conference" or presentation is private to the meeting room - unless the door is open if 5GHz is used. If 3.4GHz is used, you will be able to intercept the activity inside the meeting room through windows. If you use 2.4 - anyone outide the meeting room may intercept the activity on the inside.

A 5.4GHz phone would not work with a base unit in one room and the handset in another. You will need a 4W transmitter to get through a wall - or higher. I would NOT have that next to my head.

Mitel Do a similar solution to the Cisco Kit. It works off a standard wireless access point (the same as you use for data). If you pair this with there 6010 teleworker solution you can use a wireless phone in starbucks !!! Lets see cisco do that!!!

This is a Siemens Gigaset Skype USB adapter that works with some of their regular DECT phones:

http://www.skype.com/company/news/2004/siemens.html

"The adapter works with the recently launched Gigaset C340/345 and Gigaset CX340/345isdn, Gigaset S440/445 and Gigaset SX440/445isdn, Gigaset S645 and Gigaset SL440."

http://www.siemens-mobile.com/gigasetm34usb

Also Skype sells this (Olympia Cordless DUALphone) cordless phone:

http://www.skype.com/go/shop.olympia.buynow