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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
4 ports conforming
MD-77
to ITU-T-G.703,
2.048 Mbit/s,
DSUB-25
connector
TM-77
IOA77-1F
4
E1/G.703 P
X
LESIOCHRONOUS
O
PERATING
Optical ports
card to TM-72
telecommunication rack
2x SC
desktop version
1
M
ULTIPLEXER
M
ANUAL
Version
Management
MD-91
supervision
module in TM-
72 rack
RJ-45
connector
Power supply
18÷60V DC
36÷60V DC
230V AC
May 2007
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