Wideband Digital Data Service

What is Wideband DDS?

Wideband DDS (WDDS) is a high capacity high speed Digital Data Service provided by Telecom New Zealand.
At present no other Telcos in NZ can provide a comparable or similar service.
Transmission speeds between 64Kbits/sec and 1920Kbits/sec are available in 64Kbit increments. WDDS is a point to point DDS service and supports the X21 interface, although other interfaces such as G703 may be available.

WDDS is implemented over a 2Mbit data link. No matter how many 64Kbit channels are initially required a full 2Mbit bandwidth system is installed at each drop site for the WDDS. This provides the capability to have all thirty 64Kbit channels available for a 1920Kbits/sec link.

In common with most other Telecom DDS services the WDDS is a managed service. Faults in the circuit or faulty NTU equipment will cause an alarm and if necessary a line repair technician or data technician will be sent out to repair the problem. Turnaround time on fault repair is quite short, Telecom appear to treat WDDS circuits with urgency when it comes to repairs.

Installation and costs

Installation will require the local Telecom exchange to be capable of handling a 2Mbit circuit. Not all exchanges can do this and Telecom are not always prepared to undertake the upgrade in residential area exchanges. In other cases they may quote some additional cost to part or completely pay for the exchange upgrade.

There is an horrific basic installation charge for the 2Mbit circuit.
This is $4000 per end or $8000 in total.
If the customer already has a 2Mbit circuit installed at any of the WDDS drop sites then the installation for a new 2Mbit circuit reduces to $2800 for that site. The existing 2Mbit circuit can be for other Telecom related services such as Primary Rate ISDN. Even with such a reduction the installation cost can still be $6800 or at best $5600.
If there is an existing 2Mbit circuit at one of the WDDS drop sites BUT the circuit does no belong to the customer then it pays to discuss this with Telecom and perhaps try to get the existing circuit owner to get the new circuit in their name, hence paying only $2800 installation fee. The circuit ownership can then be changed to its proper owner for Telecom billing purposes. Most Telecom account managers will allow the reduced installation fee from the start as even they can appreciate the stupidity of messing about with different people to save $1200.


A more recent policy (1999) concerning WDDS installation fees is that Telecom NZ are now prepared to waive all installation fees ($8000 wow!!!) if the customer is prepared to commit to a minimum contract period of 12 months. If the DDS is removed or for any reason is no longer required within this 12 month period then the full installation fees have to be paid.

WDDS cannot share a 2Mbit circuit with any other services that also use a 2Mbit circuit, ie you cannot have several 64Kbit channels used for PRI ISDN and several others used for WDDS. Although there is now router equipment available that will allow this Telecom have not yet (as of May 1996) made such options available.
In any case you shoud discuss this possibility (if you may need it) with your account manager who should be able to put you in contact with the appropriate Telecom technical staff.

Installation is in two distinct phases for each end of the WDDS link.
First a 2Mbit circuit has to be installed and certified as operational.
Second a data technician will install an NTU at each end and commission the WDDS.

The physical installation at each site requires two copper line pairs (and perhaps a third for monitoring purposes). These will be extensively tested by Telecom Design and Build staff to ensure their reliability and suitability for the WDDS circuit. These copper pairs are connected into a wall mounted terminator (CLTE).
This contains logic and timing control cards for up to two 2Mbit circuits. Both logic cards are usually installed even if only one is connected. The wall mounting case is approx 250mm wide, 200mm tall and 100mm deep. It consists of a metal chassis into which the two logic cards are mounted via rails into a two slot backplane. Power for the cards is taken directly from the copper pairs so the unit does not require an AC power outlet. A plastic cover clips over the chassis and there is a window on top of the cover that allows two rows of LEDs to be viewed. There is one row on each logic card and these indicate the state of each 2Mbit circuit. Also on top of the cover is a small panel that can be opened to reveal a set of minature slide switches, two to the right of cover and two to the left. In normal operation all switches should be in the rightmost setting. The right side switch nearest to the cover opening will place the circuit in loopback if the switch is moved to left. These switches are generally not user configurable.
The installation technicians (from Design and Build) will label the cover with the circuit designations (not the WDDS circuit number but a number referring to the 2Mbit circuit). This number usually consists of a code for the Telecom exchange the 2meg circuit is connected to plus a number that is the next number in sequence for the total 2meg circuits installed in the customer premises.

WDDS monthly costs

From mid 1999, Telecom NZ have restructured the pricing of all DDS services. The previous charging method that used delivery point fixed charges plus a transmission charge that was based on distance (or step) has been totally replaced by a much simplified one cost scheme.
This means that no matter what the distance in New Zealand between the connection points for a DDS the cost is based only on the speed of the DDS link.

For example a 256k Wideband DDS (using four timeslots from a 2meg carrier) is now $1200 per month when one end of the link is connected into a stacked wideband (this is the usual type of connection service an ISP can provide) or $1820 per month for a normal 256k WDDS.
Compared to a D step 256K WDDS in the old pricing scheme, still connecting to an SWDDS at an ISP, of over $5000 per month, this new pricing represents a very significant cost saving.

These new prices show the rather ugly profits Telecom NZ were making from DDS services and it is only due to the recent competition from newer technologies, especially radio, that have forced Telecom to adopt a more realistic pricing, more inline with pricing that has been available in USA for many years.
Thank God for competition.

Internet connections and WDDS

WDDS is really only a feasible option for an Internet connection when it is known that the connection bandwidth will be increasing over the short to medium term. For longer term applications the WDDS at lower speeds of 64Kbit and 128Kbit is not cost effective when compared to ordinary DDS. The high access and local tail circuit charges for the 2Meg bearer mean that a minimum speed of 256K is necessary to justify these charges.

WDDS allows an excellent growth path for link capacity as it is possible to start with a low capacity 64Kbit to 128Kbit bandwidth then add to this in 64K increments as required.

Routers for WDDS

Any router that will work with standard DDS will also work with the lower speeds of WDDS, 64K and 128K. Although there are quite a few low cost but limited total bandwidth routers available all of these that can provide 64kbit or 128Kbit total bandwidth will work with WDDS.

Examples of such limited bandwith routers are the ACE 18x0 series, the Spider ATTO series, Cisco 200 and 700 series, Planet internal synchronous controller.
For WDDS at speeds above 128Kbit then full bandwidth synchronous serial ports and sufficient processing capability in the router are required. ACE 27xx,37xx and 47xx series routers, Cisco 25xx series, 4x00 and 7x00 series routers, and Spider MEZZA series routers all provide this capability.

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Last modified: 5 July 1999.