4
X
E1/G.703 P
LESIOCHRONOUS
M
ULTIPLEXER
O
PERATING
M
ANUAL
IOA77-1F
1
May 2007
1 O
VERALL CHARACTERISTICS
1.1 Application
TM/MD-77 linear circuit device enables full duplex transmission of four digital signals
at the bit rate of 2.048 Mbit/s in accordance with ITU-T G.703 via a fiber optic line.
TM/MD-77 devices can operate with PCM-30 terminal equipment, telephone switches
or other optional signal sources at the bit rate of 2.048 Mbit/s equipped with the same interface.
The devices are completely transparent for the content of the transmitted signal; it can be
a non-framed or framed signal - provided it complies with the requirements of the G.703
recommendation.
All TM-77, MD-77, TM-76, MD-76 and TM-44 devices can operate with each other if
connected via a fiber optic line. If TM/MD-77 4-channel device is connected to MD-76 or TM-
76 single-channel device, transmission with the first E1 channel is possible.
The optical signal can be transmitted via a couple of single-mode or gradient optical fibers
depending on the version of the device.
Transmission via SM fiber can be realized with devices equipped with LASER type
transmitter.
Transmission via MM fiber can be realized only with devices equipped with both LED
and LASER type transmitters.
1.2 Basic
features
Table 1.
Basic features of the devices
Symbol
Electrical ports
Optical ports
Version
Management
Power supply
MD-77
card to TM-72
telecommunication rack
MD-91
supervision
module in TM-
72 rack
18
÷
60V DC
TM-77
4 ports conforming
to ITU-T-G.703,
2.048 Mbit/s,
DSUB-25
connector
2x SC
desktop version
RJ-45
connector
36
÷
60V DC
230V AC
