Lanex TM-78 Operating manual - 3. F
10Base-T/100Base-TX/E1 converter
Operating Manual
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IOA78-1C 7 January 2005
3. F
UNCTIONAL DESCRIPTION
3.1. Rule of operation
The converter is equipped with 3 ports. Two ports are used for connecting external
network segments. One port is equipped with an MDI output jack and the other has two output
jacks, an MDI and an MDIX (switched transmission and reception signals cables). The Ethernet
segment can only be connected in the second port to one of the MDI or MDIX jacks. Regardless
of the device connected (NIC, hub, switch), ‘straight’ cable can always be used for that port. The
third port is used for connecting E1/G.703 line.
Ethernet frame received from any port, located in time slots of G.704 frame in the form of
digital channel n x 64 kbit/s, n from 1 to 31 and sent to PDH or SDH telecommunication network
through G.703 interface. To the opposite direction of transmission, G.704 frame is received from
the telecommunication network, Ethernet frame is extracted and sent to a relevant port of the
switch, depending on where the connected station is located. The device filters local traffic within
Ethernet network connected to switch ports and only retransmits inter-network traffic to remote
network segments. Device configuration and operation status monitoring, as well as operation of
the managing application with LNMP protocol is performed through RS-232 electrical interface.
The Ethernet interface serves two implementations of the physical layer, rated 10 Mbit/s
and 100 Mbit/s, with an option of automatic negotiation, which ensures connection at a maximum
available rate – Table 3-1. The mode of connection is signaled by LEDs on the front wall.
Table 3-1. Sequence of connection choice in automatic negotiation
Sequence Connection
mode
1 100BASE-TX
full-duplex
2 100BASE-TX
3 10BASE-T
full-duplex
4 10BASE-T
The converter regularly reviews the stored addresses in the MAC source address table,
deleting the ones residing there for over 300 seconds.
3.2. Clock
The converter may send data to transmission direction E1/G.703 with a clock from two
sources:
• from internal quartz generator, frequency 2.048 MHz ±50 ppm, operating in MASTER
mode
• from clock retrieval systems of opposite direction of transmission E1/G.703, operating in
SLAVE mode
3.3. Diagnostic and signaling systems
The converter automatically checks the parameters of line interface E1/G.703 and Ethernet
interface signal. It detects and signals the following conditions and volumes:
E1/G.703, G.704 line interface:
• loss of signal at interface input
• loss of frame
• excess of error rate (violation of HDB3 code) 1x10
-3
and 1x10
-5
in incoming signal
• AIS signal receipt
• receipt of alarm bit from remote device in zero slot of G.704 frame