DS4-2499D
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10. Operation
(1) The data frames to be sent to the receiving unit are first sent to the transmission buffer of the
equipment from an external device. The data in the transmission buffer is sent to the receiving
unit at a converted rate of 2.5Mbps.
* Note. If a unit not supporting the flow control (IEEE802.3x) is connected in full-duplex mode,
some data frames may be lost when data exceeding the buffer capacity (16kB) is sent at a time.
If any data frame is lost, try to take the following actions.
Action (1): Set both type A and B units to half-duplex mode.
In half-duplex mode, a back pressure is applied in case of buffer overflow. The
sending unit is requested to transmit data again after waiting for a while.
Action (2): Increase the interval after each transmission by the sending unit.
Reduce the size of each data to be sent at a time to about 14kB and increase the
interval before sending the next data.
As a guide, the transmission intervals shall be approximately equivalent to the data
size (in bytes) multiplied by 4µs.
Action (3): Change the device connected with the optical transmitter to a one supporting the flow
control to automatically increase the intervals at which data is transmitted.
The SOT-EQ80A/B supports the flow control.
The transmission intervals are automatically adjusted between the units in case of
buffer overflow.
When connecting the unit, activate the auto negotiation function.
Action (4): Use a protocol such as TCP to retransmit the lost frames.
(2) The data frames sent back from the receiving unit are sent to the reception buffer in the equipment.
The data in the reception buffer is sent to the external device at a converted rate of 10Mbps.
(3) Functions of sending data indicator lamp (SD) and receiving data indicator lamp (RD)
Sending data indicator lamp (SD) blinks in red when sending input is active.
Receiving data indicator lamp (RD) blinks in green when receiving input is active.
(4)When optical path is shielded, the receive indicator lamp goes off, and no data can be
sent any longer. Reception level is not displayed, either, at the receiving unit.
(5)Functions of link indicator lamp (LINK) and full-duplex indicator lamp (FDX)
Link indicator lamp (LINK) shows green when the network connection with the external device
connected to the signal connector is normal.
Full-duplex indicator lamp (FDX) shows green when the network connection with the external
device connected to signal connector is in full-duplex mode.
(6) Aux. output operates as shown below.
1) DL: Transistor turns on when the data link is normal.
2) ALM: Transistor turns off when the reception level indicator lamp (LEVEL 1) is off.
(7) The statuses of indicators and subsidiary outputs change as shown below when the beam is received
or interrupted.
