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OTS-155 is basic STM-1 transmission equipment and has optical interface with standard STM-1 transmission rate, E1 interface, Ethernet interface, and 2 light directions. OTS-155 is one choice of optical network terminal equiptments.

OTS-155 has 252×252VC12 / 12×12VC3 / 4×4VC4 non-block crossing function. Its network management supports warning, monitoring, maintenance, supervision and management functions.


There are 2 optical interfaces on the main board. 2 Ethernet ports extensible, with another expansion slot for 16×E1.

OTS-155 Signal Processing Slot List
Module Introduction
16×E1 card 16 channels of E1(ballanced/unballanced)
Ethernet card 10M/100M auto adapted Ethernet


Frame Parameter

The framework of OTS-155 is made of compound metal, 19 inche external width, 1U height, 24cm length.

This equipment can be located on any stable base, and can be also screwed through mounting hole to 19 inch cabinet.


Port Physical Parameter

Name Description
E1 port OP interface, connected to ddf with L9 coaxial connector.
Optical interface FC/SC
LAN Interface RJ45
Engineering orderwire RJ11
NM port DB9(socket) & RJ45


Port Electrical Parameter

Optical Interface

Code rate: STM-1

Transmit power: -8∼2dBm

Receive sensitivity: -28∼-34dBm

Optical port: 1∼2 STM-1

E1 Interface

Capacity: 16
Transmission Type: HDB3
Transmission Rate: 2048Kbit/s
Permissible Deviation: ±5×10E-5
Impedance at E1 Interface: 75Ω/120Ω
E1 Signal Amplitude: 2.37V/3V

LAN Interface

Specification: IEEE802.3
Bandwidth: 100Mbit/s
Applicable Ethernet rate:
            10M/100M auto adaptation
Work mode: Half-duplex/full duplex
Rate Control: By NM software

Clock option

2048KHz external clock
STM-1 timing source inputs
STM-1 tributary clock
SSM function
working mode:
            locked/keeping/Internal mode
priority: NM software control


Capacity: 25
Calling function:
all call, selective call, group call
Code mode: A-law/µ-law
Interface: VF
Ring frequency: 450Hz
Ring mode: buzzer

Working environment

Feeding mode: -48V/DC
Voltage range: -48V±15%
Operation temperature: 5℃∼45℃
Relative humidity: ≥95%(T≥25℃)


Point to point mode

Link mode

Ring mode



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