Telos Zephyr Xstream User Manual page 168

These configurations would be similar to using DDS lines (see below), however it gives the
remainder of the T1 capacity for some other purpose between the two sites in question.
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DEEP TECH NOTE!
If you can afford a full T1 for your application, then you should be considering options that
do not require use of audio compression.
We recommend that option for STLs and other critical audio paths. Equipment is available
from a variety of vendors to allow uncompressed audio transmission over T1 circuits.
Zephyr Xstream's V.35 Single offers audio connectivity at an intermediate cost while
offering the high fidelity and robustness possible with MPEG at low compression ratios.
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HOT TIP!
When ordering dedicated lines, such as DDS or T1, which will not be used for interstate
access, be sure to file an "Interstate Access Charge Exemption Form". This should result in
significant savings in monthly fees.
Digital Data System (DDS)
A DDS circuit is a dedicated, "nailed‐up" connection between two specific locations. Also
referred to as dedicated digital service. Technically, DDS service includes rates up to 56kbps.
Two such lines can be used to provide stereo audio. However, "dedicated digital lines" are also
available at higher rates such as 64kbps. In Europe we've even seen 128kbps dedicated lines.
Use of this service requires an appropriate CSU/DSU (Channel Service Unit/Data Service Unit) at
each end to interconnect the line with the Zephyr Xstream. One popular model is the Adtran
DSU 56/64 (Adtran part # 1200062L1) see www.adtran.com or your Adtran dealer.
Other Possibilities
Any transmission channel that can convey synchronous digital signals in real time, may be used
with the Zephyr Xstream. Possibilities include T1, satellite links (Including the portable Inmarsat
terminals), spread‐spectrum RF transmission systems, and ATM. The error rate should be 1 e‐7
or less. The communications equipment must support V.35 or X.21. An adaptor cable may be
required if this equipment does not support the usual connector. The Xstream expects this
communications equipment to provide a clock on the X.21 or V.35 connector.
When considering a technology (such as ATM) it is essential that your service has a "Committed
Information Rate" equal to the required bit rate (i.e. 56, 64, 112, 128, 256, or 384 kbps) and that
it is a "Constant Bit Rate" service.
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USER'S MANUAL
Section 9: The V.35/X.21 Interface Option 156