User guide

Technical Description
Sealevel Systems COMM+16.PCI Page 3
Technical Description
The Sealevel Systems COMM+16.PCI provides a PCI interface adapter with 16 RS-232 asynchronous serial ports
for industrial automation and control applications.
The COMM+16.PCI utilizes the 16C854 UART. This chip features programmable baud rates, data format, interrupt
control and industry leading 128-byte transmit and receive FIFOs.
Connector Pin Assignments
DB-25 (RS-232 DTE) (DB-25 Male)
Signal Name Pin # Mode
GND Ground 7
TD Transmit Data 2 Output
RTS Request To Send 4 Output
DTR Data Terminal Ready 20 Output
RD Receive Data 3 Input
CTS Clear To Send 5 Input
DSR Data Set Ready 6 Input
DCD Data Carrier Detect 8 Input
RI Ring Indicator 22 Input
Technical Note: Please terminate any control signals that are not going to be used. The most common way to do this
is connect RTS to CTS and RI. Also, connect DCD to DTR and DSR. Terminating these pins, if not used, will help
insure you get the best performance from your adapter.
DB-68 (Micro MDB-68 Female)
Port # 1 2 3 4 5 6 7 8
TD 1 9 19 27 35 43 53 61
RI 2 10 20 28 36 44 54 62
DCD 3 11 21 29 37 45 55 63
DTR 4 12 22 30 38 46 56 64
RTS 5 13 23 31 39 47 57 65
DSR 6 14 24 32 40 48 58 66
RD 7 15 25 33 41 49 59 67
CTS 8 16 26 34 42 50 60 68
GND 17 17 18 18 51 51 52 52
Both cables are interchangeable and can be used on either connector. The top connector supports Ports 1-8
and the bottom connector supports Ports 9-16.