DASS2 Converter: Technology

What are the differences between DASS2 and Euro-ISDN?

There are a number of low-layer protocol differences which do not matter in daily use. As a technician you would probably be interested in the following facts:

Connectors and Wiring: The most obvious difference between a typical DASS2 and a Euro-ISDN installation is the wiring. DASS2 circuits are mostly delivered by means of coaxial cords with BNC sockets, whilst Euro-ISDN is delivered on a two pair copper cord with RJ 45 sockets. The Parlay Protocol Converters are available with both BNC and RJ45 sockets. If you face a mismatch of Parlay socket and DASS2 circuit, a Balun can be used to convert between the mechanics as well as the impedances.

Number Presentation: In DASS2 only significant digits are passed to the called PBX. A typical call contains the four digit DDI number, but not the pilot number. In Euro-ISDN, the number received typically consists of the pilot number including the DDI. Sometimes even the area code is included. The Parlay Protocol Converters add or strip off the pilot number where required.

Channel Handling: In DASS2 each of the 30 communication channels is considered a unique line with its own characteristics. Such DASS2 lines may be assigned a particular service (Category 1 call, Telephony Call) or a group of DDIs. In Euro-ISDN the B-channels are just a group of transportation means for any kind of information. Call related service information is provided during call establishment. The Parlay Protocol Converters cater for this difference by routing the correct service onto the proper DASS2 communication channel.

Disconnect Causes: When calling a busy subscriber on DASS2, the BT network returns the Cause Code 8 BUSY. Causes are used in Euro-ISDN as well, however the numbering and naming are different. A busy subscriber returns Cause Code 17 meaning USER BUSY. The Parlay Protocol Converters deal with correct mapping of causes.

Which Supplementary Services are supported by the Parlay DASS2 Protocol Converters?

The DASS2 protocol is quite powerful. It offers a number of supplementary services which were revolutionary at the time of release. Even today DASS2 can easily compete with Euro-ISDN with regards to services.

These DASS2 Supplementary Services will still be available on your DASS2 PABX after having installed the Parlay Protocol Converter:

CLI     Calling and Called Line Indication
CCI     Call Charge Indication
CCRD Call Charge Rate Data
BTP     Backward Transmission Path
ICB      Incoming Call Barring
OCB     Outgoing Call Barring

Are there any limitations as regards to DASS2 to Euro-ISDN protocol conversion?

Limitations only apply, if a service in one protocol does not exist in the other protocol. This is for instance the case with the COLP service in Euro-ISDN. Connected Line Identification Presentation passes the phone number of the person, who answered the phone, to the calling party. There is no such service in DASS2.

Does Advice of Charge (AOC) work even with the Parlay Protocol Converter?

Yes, it does work! If you see the call charges on your DASS2 feature phone�s display today, you will see them even after installation of the Parlay Protocol Converter.

The Parlay Protocol Converter even generates call charge indication by itself! The call routing table in Parlay may contain the call charges as well, which will allow you to overcharge certain calls in for instance hotel applications.

Can I install and set up the Parlay Protocol Converter myself?

If you are an experienced telecoms technician, you can. You would need a Microsoft Windows setup tool called RoutMaker.

Here you will find a DASS2 Converter Instruction Guide.