Browse Prior Art Database

T1 LINK TO DDS LINE CONVERTER

IP.com Disclosure Number: IPCOM000007844D
Original Publication Date: 1996-Nov-01
Included in the Prior Art Database: 2002-Apr-29
Document File: 2 page(s) / 112K

Publishing Venue

Motorola

Related People

Gordon T. Fadie: AUTHOR

Abstract

Telecommunications systems consist of two dis- tinct areas of responsibility: the user side and the network side. Users interface their equipment to the network with some type of communications termi- nating equipment. Examples of these include multiplexers, channel banks, Tl CSUs and DSWCSUs. (Analog modems too, but this devel- opment focuses on digital communications.) The pur- pose of network terminating equipment is to con- vert the electrical (RS-232, V35 EIA-530, etc.) interface on the user's equipment to a 4-wire inter- face compatible with the carrier's digital network.

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Technical Developments

l-l LINK TO DDS LINE CONVERTER

by Gordon T. Fadie

1 .BACKGROUND

  Telecommunications systems consist of two dis- tinct areas of responsibility: the user side and the network side. Users interface their equipment to the network with some type of communications termi- nating equipment. Examples of these include multiplexers, channel banks, Tl CSUs and DSWCSUs. (Analog modems too, but this devel- opment focuses on digital communications.) The pur- pose of network terminating equipment is to con- vert the electrical (RS-232, V35 EIA-530, etc.) interface on the user's equipment to a 4-wire inter- face compatible with the carrier's digital network.

  Generally, network terminating equipment has one or more electrical interfaces, such as RS-232, on the user side and a 4-wire interface on the net- work side. The 4-wire network interface will either be DDS or Tl. The network terminating equipment typically derives its timing from the incoming sig- nal from the network. This insures synchronization from end to end because both ends of the circuit are timing off the same source.

vert to a 4-wire DDS signal to be compatible with the carrier's network. Problems with this approach include too much equipment and difficulty achiev- ing synchronization.

  Another solution might be to add a DDS mod- ule to the channel bank and access the network through it. Unfortunately, channel banks and multiplexers don't allow internal channel-to-channel cross-connects. Nor do they allow the user to configure the channel bank or multiplexer to derive timing from the DDS module. So again, synchroni- zation is lost.

3. SOLUTION

  The "Tl LINK TO DDS LINE CONVERTER" takes a Tl input from the user equipment and strips off all but one time slot. It takes this time slot to a 4-wire DDS CSU type interface where it connects to the carrier's DDS network. It would accomplish this by counting all 193 bits in Tl frame, take the first 8 bits and divert them From the Tl interface to the DDS interface. At the receiving end, the oppo- site process takes the incoming DDS signal and puts it into the appropriate time slot of the...