Crocus
Inverse Multiplexer
- Connects up to 8 Mbps serial
data over several E1 links
- Automatic speed adaption
in case of E1 link loss
- Advanced free maintenance
software
- Manageable under HP OpenView®
- Modular plug-in DTE interfaces
for maximum flexibility
- and efficient stock management

The Crocus
Inverse Multiplexer provides transparent transmission
of synchronous data at speeds up to 7808 kbps on a serial
interface using multiple 2 Mbps E1 lines. The equipment enables
one to cross the 2 Mbps barrier without having to adapt the
installed user applications, which can be operated at their
fastest rates.
The system is
based on an extension of recommendation ISO/IEC 13871 (1995),
which offers an efficient bonding mechanism for multiple E1
lines. These E1 lines may have a difference in throughput
delay as high as 64 msec so different routings of the constituent
E1 lines can be used. In addition, an automatic fallback step-up
mechanism permits the user to add or suppress E1 lines and
so to adapt dynamically the user speed in multiples of 1952
kbps.
A complete range
of serial plug-in interface boards makes the Crocus Inverse
Multiplexer ideal for interfacing with almost any high-speed
application. Traditional interfaces such as V.35, V.36, X.21
or RS-530 and also direct 10BaseT connections with integrated
bridge functionality are available. All these interface boards
can be exchanged in only a few seconds.
Typical topologies
include high-speed serial data interconnectivity for direct
point-to-point connections and also data services in combination
with E1 Networks, like DACCS (Digital Access Cross Connect
Systems) or SDH (Synchronous Digital Hierarchy) backbones.
If the equipment is used in combination with HDSL modem technology
(e.g. Crocus HDSL), the existing local loop copper infrastructure
can be used for this high-speed data service. In the example
below, a user application (router) is connected with a high-speed
serial connection (V.36, 7808 kbps) to a Crocus Inverse
Multiplexer. The Crocus Inverse Multiplexer E1
lines are connected to 4 HDSL links, which use regular twisted
copper pairs for making the connection to a Digital Access
Cross Connect System (DACCS). The DACCS will route the E1
lines to an access point of a frame/relay backbone, where
the different E1 lines are regrouped by another Crocus
Inverse Multiplexer before the user data enter the frame/relay
backbone infrastructure.

Typical Application:
High speed access to a packet switched backbone through a
DACS
The equipment
is shipped with a unique and free Windows application, which
gives the user a powerful maintenance tool for both the local
and the remote equipment. It provides not only for configuration
of the equipment but also for an interactive picture, status
interrogation, real-time performance monitoring, and statistics
retrieval.
In addition, the
Crocus Inverse Multiplexer has an Ethernet connection,
which allows for SNMP management. Management modules are available
for different integrated management platforms, like HP OpenView®.
On those platforms, one can combine the management of the
Crocus Inverse Multiplexer equipment with the management,
for example, of modem and router
TECHNICAL SPECIFICATIONS
Inverse
Multiplexing
Number of E1 links |
up to 4 |
Maximum delay variance
between links |
64 msec |
Throughput delay |
50 µsec + variance between
links |
Framing overhead |
1.6 % |
Net user speed per E1
link |
1952 kbps |
Performance Monitoring
per E1 link |
End-to-end CRC-4 |
E1 Link
interfaces
Applicable standards |
ITU-T G.703, G.704, G.732 |
Jitter performance |
ITU-T G.823 |
Nominal line data rate |
2048 kbps |
Line code |
HDB3 |
Line connection |
120 ohm balanced, RJ45
connector |
|
75 ohm unbalance, BNC
coaxial connectors |
Performance Monitoring |
G.703 CRC-4 (configurable) |
Station clock interface
Nominal rate |
2048 kbps |
Line code |
HDB3 |
Line connection |
120 ohm balanced, RJ45
connector |
|
75 ohm unbalance, BNC
coaxial connectors |
Ethernet
LAN Interface (management)
Connector |
RJ45 |
Operation |
10BaseT Ethernet |
Console
Port
Connector |
9-pins subD
Female V.24/RS-232 |
Data Rate |
9600 bps,
asynchronous, 8N1 |
Clocking Schemes
External transmit clock
(station clock) |
Transmit clock slaved
on E1 receive clock with possibility for automatic E1
channel source selection |
Internal transmit clock |
High-speed
data interface
Clocking Speed |
1952, 3904,
5856, 7808 kbps, following the number of E1 links used |
Automatic
fallback to next lower rate in case of E1 link failure |
Serial interfaces
available:
V.35 |
ISO 2593 (female
1,6mm pin) |
V.36 |
ISO 4902 (DB37
female) |
X.21 |
ISO 4903 (DB15
female) |
RS-530 |
ISO 2110 (DB25
female) |
Bridge |
10BaseT (RJ45) |
|
Conform IEEE
802.3 |
|
Integrated
Bridge functionality |
Front
panel Indicators
General |
PWR
TST
|
Power
Test Indicator
|
Ethernet |
LNK
COL
TXD
RXD
|
Link Integrity
Data Collision
Transmit Data
Receive Data
|
For each E1 |
LOS
LOF
AIS
ERR
|
Loss Of Signal
Loss Of Frame synchronisation
Alarm Indication Signal
CRC-4 performance problem
|
DTE |
TXD:
RXD:
|
Transmit Data
(circuit 103)
Receive Data (circuit 104)
|
Tests
Local Analog Loopback (Loop3)
for each individual E1 line
Local Line Loopback (Loop4)
for each individual E1 line
Local Digital loop (Loop2)
for high-speed user interface
Remote digital loop (remote
Loop2) for high-speed user interface
Integrated BER testing conform
ITU-T O.151 (215-1 pattern)
Mechanical data
Desktop version |
H x W x D:
50 x 430 x 270 mm weight: 4.3 kg |
Rack-mount
version |
H x W x D:
43 x 482 x 270 mm weight: 4.6 kg |
Environmental
Requirements
Ambient operational
temperature
Storage temperature
Maximum altitude
Relative humidity
|
0° C to 50°
C
-25° C to +70° C
3000 m
0% to 95% non-condensing
|
Power
Requirements
Power voltage |
90-264 Vac,
47-63 Hz 20-70 Vdc |
Maximum power
consumption |
25 W |

The Crocus
Inverse Multiplexer
|