What are Modem Lights?

Optical modem, also known as single-port optical transceiver, is a three-piece optical fiber transmission equipment developed for special user environments. The device uses a large-scale integrated chip, with simple circuits, low power consumption, high reliability, complete alarm status indication and perfect network management functions.

Lightcat's equipment uses large-scale integrated chips, simple circuits, low power consumption, high reliability, complete alarm status indication and perfect network management functions.

An optical cat is a device similar to a baseband modem (digital modem). Unlike a baseband modem, it is connected to a fiber optic dedicated line and is an optical signal. It is used for the conversion of photoelectric signals and interface protocols in a wide area network. The access router is a wide area network access. The optical transceiver uses the conversion of optical signals in the local area network, but only the signal conversion, without the conversion of the interface protocol.

Simply speaking, the Ethernet optical cat is mainly used when the distance is more than 20KM, and it needs to be transferred through optical transmission equipment such as SDH / PDH in the middle. Generally, the speed of the optical cat is packed on a 2M circuit, so the difference between the optical transceiver of the optical cat is also its speed, the optical cat is 2M, and the optical transceiver is 100M.

General application scenarios:

Customer-Ethernet optical cat-optical cable-E1 optical cat-2M cable-SDH optical transceiver-another office SDH optical transceiver-PDH optical transceiver-E1 to Ethernet protocol conversion-customer equipment (Ethernet switch or computer, etc.) Of course, there are also V.35 light cats, V.24 light cats, RS-232 light cats and so on.

The optical modem is composed of transmitting, receiving, controlling, interface and power supply. The data terminal equipment provides the transmitted data in the form of a binary serial signal, which is converted into an internal logic level by the interface and sent to the transmitting section, and the signal required by the modulation circuit is transmitted to the line by the modulation circuit. The receiving part receives the signal from the line, restores it to a digital signal after filtering, inverse modulation, and level conversion and sends it to the digital terminal equipment. Similar to the modulation and demodulation of high-frequency carriers in electrical communications, optical modems can modulate and demodulate optical signals. Regardless of whether it is an analog system or a digital system, the electrical signal with information input to the optical transmitter is converted into an optical signal through modulation. The optical carrier is transmitted to the receiving end through the optical fiber line, and then the receiver converts the optical signal into an electrical signal through demodulation. ^[2]

A single E1 optical transceiver is a device that modulates the E1 signal of G.703 onto an optical fiber for transmission.

Single V.35 optical transceiver: A single V.35 optical transceiver provides a framed N * 64Kbit / s V.35 data interface.

Ethernet optical transceiver (2M bandwidth): 2M bandwidth Ethernet optical transceiver provides a 2M bandwidth Ethernet interface. (Use with single E1 optical transceiver and E1 converter).

Ethernet optical transceiver (10M bandwidth): 10M bandwidth Ethernet optical transceiver provides one Ethernet interface and four E1 interfaces. The bandwidth of the Ethernet interface (2-10) M is adjustable. When the bandwidth is increased, the E1 interface needs to be occupied, and each additional 2M bandwidth requires an E1 interface. When the Ethernet bandwidth is 10M, four E1 interfaces are unavailable. (Use with 5E1 optical transceiver and 5E1 converter).

Integrated network management rack: The integrated network management rack can be mixed with various modems of optical modems, converters and optical transceivers. The unified network management card can meet users' centralized network management and maintenance of all equipment. The device provides 16 equipment business slots, network management slots and 2 power supply slots.

Optical Modem Technical Index

Light mouth

Light wavelength: 1310nm

Transmit optical power: not less than -10dBm

Receiving sensitivity: not more than -37dBm

Connection method: FC

E1 interface

Nominal bit rate: 2048Kbit / s

Line coding: HDB3

Impedance: 75

Meets ITU G.703 recommendations

V.35 interface

V.35 standard rate supports pure 2048Kibt / s and N * 64Kbit / s, which can be selected according to the actual needs of users

The DTE and DCE methods can be determined according to the line. The selected data and clock level are in accordance with ITU-T Recommendation V.35.

Ethernet interface

Interface speed: support 10 / 100M adaptive access

Transmission rate: support pure 2M and transparent transmission pure 10M, can choose according to the actual needs of users

Duplex mode: supports half-duplex, full-duplex mode

Physical interface: RJ45 newer versions can also support RJ11

Fully compliant with IEEE802.3 LAN protocol standard

How Optical Modems Work

The baseband modem consists of transmitting, receiving, controlling, interface, control panel and power supply. The data terminal equipment provides the transmitted data in the form of a binary serial signal, which is converted into an internal logic level by the interface and sent to the transmitting section, and the signal required by the modulation circuit is transmitted to the line by the modulation circuit. The receiving part receives the signal from the line, restores it to a digital signal after filtering, inverse modulation, and level conversion and sends it to the digital terminal equipment. An optical modem is a device similar to a baseband modem. Unlike a baseband modem, it is connected to a fiber-optic dedicated line and is an optical signal.

Optical modem indicator description

Table 1: ^[3]

Indicator light	status	Description
WPS	Chang Liang	WPS function is enabled.
	flicker	A Wi-Fi terminal is accessing.
	Off	WPS function is not activated.
WLAN	Chang Liang	The WLAN function is enabled.
	flicker	There is data transmission.
	Off	The WLAN function is not enabled.
USB	Chang Liang	The USB port is connected, but there is no data transmission.
	Fast flashing (2 times / second)	There is data transmission.
	Off	The system is not powered on or the USB port is not connected.
TEL1 TEL2	Chang Liang	The TEL interface has established a connection with the voice server.
	Fast flashing (2 times / second)	The TEL interface has established a connection with the voice server and is off-hook or ringing.
	Slow flashing (1 time / 2 seconds)	The TEL interface is registering with the voice server.
	Off	The TEL interface is not connected to the voice server.
LAN1 LAN4	Chang Liang	The Ethernet connection is normal.
	flicker	The Ethernet interface has data transmission.
	Off	The Ethernet connection is not established.
LOS / PON	As shown in table 2
POWER	Steady green light	Power is on.
	Off	Power is off.

Table 2:

status Numbering	Indicator status		Description
	PON	LOS
1	Fast flashing (2 times / second)	Off	The PON terminal is establishing a connection with the upper-layer equipment.
2	Chang Liang	Off	The PON terminal has established a connection with the upper-layer equipment.
3	Off	Slow flashing (1 time / 2 seconds)	The PON terminal is not connected to optical fiber or no optical signal.
4	Fast flashing (2 times / second)	Slow flashing (1 time / 2 seconds)	The received optical power is not within the normal range of optical reception. CLASS B + range: -27 dBm to 8dBm CLASS C + range: -30dBm--8dBm
5	Off	Chang Liang	The PON terminal is disabled by the upper layer device or the PON terminal emits abnormal light. Please contact the service provider.
6	Off	Off
7	Fast flashing (2 times / second)	Fast flashing (2 times / second)
8	Slow flashing (1 time / 2 seconds)	Slow flashing (1 time / 2 seconds)	The PON hardware is faulty.