Impulse 2807 - Manual (Page 8)

© Sealevel Systems, Inc. - 6 - SeaLINK+8.VC User Manual
Technical Description
The SeaLINK+8.VC utilizes eight USB UARTs. These chips feature programmable
baud rate, data format, 128 byte Dual Port TX Buffer, and 384 byte Dual Port RX
Buffer. The RS-232 transceivers support data rates up to 115.2K bps and the RS-485
transceivers support data rates up to 921.6K bps.
Connector Pin Assignments (RJ45)
Name Pin # Mode
D+ RS-485 Data + 1
RTS Request To Send 2 Output
TX Transmit Data 3 Output
GND Ground 4
NC No Connect 5
RX Receive Data 6 Input
CTS Clear To Send 7 Input
D- RS-485 Data – 8
Note: DCD, DSR, and RI are inputs that are not brought out on the RJ45 connector.
DSR and DCD are biased active and RI is biased inactive.
Interface Selection
With the unique VersaCom multi-interface connector design, both RS-232 and two-
wire RS-485 signals are always present and active on the RJ45 connectors. Simply
select the appropriate pin out for RS-232 or two-wire RS-485 on each individual
port. The unused interface on each connector should be left unconnected. All inputs
have appropriate biasing to keep them in an inactive state. If the unused interface
pins are connected to a cable, the outputs will attempt to drive the lines while the
inputs will attempt to interpret any voltage on the line as data, which can limit cable
length and may result in communication failures.