Zhone Technologies IMACS Network Device - Manual (Page 62)

Zhone Technologies, Inc. IMACS Product Book, Version 4
March 2001 Page 58
The two transmission protocol supports switched connectivity to ISDN capable switches and D channel signaling on
either a full DS0 or multiplexed 4:1 on a single DS0. The ability to multiplex 4 channels onto one DS0 allows for
more efficient provisioning. The 826361 and 826461 cards only support 3 DS0s at this time.
Another application of the BRI card is for leased line, or IDSL (ISDN Digital Subscriber Loop) as shown in Figure
18. This allows for a DDS type circuit, with 2 * 64 kbps bearer channels over a single wire pair. The leased circuit
can be any standard 2B1Q (U interface) NTU device that supports “nailed-up” (1 or 2B channels) connections and
no D channel signaling for the 826070, 826171, and 826270 cards. The 826361 and 826461 cards support a
standard non-direct OS/NE communication scheme or multipoint eoc (mp-eoc). The mp-eoc is used for sending
operations messages between the ISDN switch and NE line units.
The requirements are specified in TR-829. The performance monitoring portion of this specification will not be
implemented. For the 3-DS0 TDM, the overhead bits are transported between the LUNT and LULT as described in
TR-397, and for the 4:1 TDM, this is done in a proprietary format. This allows continued customer deployment of
D4 equipment as shown in Figure 17.
Leased Line or IDSL (2B1Q)
2B1Q
NTU
DTE DTE
IMACS
IMACS
T1/E1 carrier
Network
2B1Q
NTU
Figure 17 - IMACS BRI Card In A Leased Line or IDSL Application
C e n t r a l O f f i c e
I S D N
S w i t c h
D 4 C h a n n e l B a n k
N T 1
I M A C S w i t h
B R I T E c a r d
T 1
N T 1
I M A C S w i t h
B R I T E c a r d
T 1
Figure 18 - Use of Legacy D4 Equipment Application
BRI Card Models
In both cases, leased line and BRITE, B channels carrying voice traffic on the BRI card can be compressed through
the ADPCM card to extend the user’s Servers. The only limitation on BRI traffic is that NTUs or NT1s must be
located less than 18,000 feet from the system unit.