5
X
RS-232,485 + 2
X
E
THERNET
/2 M
BIT
/
S
G.703 (G.704) M
ULTIPLEXER
O
PERATING
M
ANUAL
IOA81-1E
10
August 2004
3 Functional
Description
3.1 Introduction
The multiplexer is equipped with two 2048 kbit/s line ports (A and B) compliant with
ITU-T G.703 and G.704 recommendations. Through these ports the device can be connected
with other telecommunication devices like SDH multiplexers, PCM-30 multiplexers or with
any other signal sources featuring with the bitrate of 2048 kbit/s and equipped with similar
interfaces.
Next, the multiplexer is equipped with five full-duplex channel ports C1
÷
C5 compliant
with the ITU-T V.28 or EIA-485 standard and two duplex channel ports C6
÷
C7 compliant
with IEE802.3 10BASE-T standard in the physical layer, allowing connecting the device with
telecommunication equipment with identical interfaces. These ports are also called „tributary
channels”.
The fundamental function of multiplexer is to transmit signals appearing in C1
÷
C7 tribu-
tary channels through 64 kbit/s time slots of 2048 kbit/s stream introduced by one of line
ports. A data signal delivered to channel ports is directed to physical input transceivers, re-
generated and then delivered to asynchronous/synchronous controllers.
The access of tributary channels to the 2048 kbit/s stream is possible thanks to the inte-
gral, configurable dropping circuit (see Fig. 12).
The dropping circuit can be configured by using a set of switches located at the front
panel. When configuring this circuit, it is possible to:
- Select tributary channels designated for transmission;
- Select the group of time slots within the 2048 kbit/s stream and assign this group to
tributary channels;
- Establish the line port (A or B) from which time slots will be dropped;
- Set operating mode for each tributary channel.
Detailed description of the configuration function and methods of dropping are given in next
sections of this manual.
C1 C2 C3 C4 C5
C6 C7
PORT
B
PORT
A
5 x RS-232/485
2 x 10BASE-T
TM-81
MULTIPLEXER 7x64k/2M
TRIBUTARY CHANNEL CONFIGURATION
TM-81
B
A
AIS
10
-3
LOF
LOS
G.703
CONFIGURATION
LNK
B
OR
A
MUX
RCV
C
C
C
C
C
C
C
C
C
C
C
1
1
1
3
4
5
7
7
7
6
2
CHANNEL DIRECTION
MODE OF OPERATION
4 5 6 7 8
1 2 3
ON
4 5 6 7 8
1 2 3
ON
4
1 2 3
ON
4 5 6 7 8
1 2 3
ON
4 5 6 7 8
1 2 3
ON
4 5 6 7 8
1 2 3
ON
4 5 6 7 8
1 2 3
ON
4 5 6 7 8
1 2 3
ON
4 5 6 7 8
1 2 3
ON
9 10
LNK
RCV
Fig. 12.
Multiplexer type TM-81: transmission ports
