SeaLevel C4-104 Series User manual

C4-104
USER MANUAL
Part # 3520, 3521, 3522
Sealevel Systems, Inc
155 Technology Place
P.O. Box 830
Liberty, SC 29657 USA
Phone: [phone]
FAX: [phone]
www.sealevel.com
TM

Contents
INTRODUCTION ........................................................................ 1
OVERVIEW ...........................................................................................1
WHAT’S INCLUDED..............................................................................1
FACTORY DEFAULT SETTINGS..............................................................1
OPERATING SYSTEM INSTALLATION ....................................................1
CARD SETUP............................................................................. 2
ADDRESS SELECTION............................................................................2
IRQ SELECTION...................................................................................3
RS-485 MODE (RTS ENABLE)...........................................................4
INTERFACE SELECTION.........................................................................5
RS-232...............................................................................................5
RS-422/485.......................................................................................5
COMBINED RS-232 & RS-422/485..................................................5
INSTALLATION.......................................................................... 6
OPERATING SYSTEM INSTALLATION ....................................................6
For Windows Users.......................................................................6
Other Operating Systems ..............................................................6
SYSTEM INSTALLATION .......................................................................6
TECHNICAL DESCRIPTION ....................................................... 7
FEATURES............................................................................................7
CONNECTOR PIN ASSIGNMENTS ...........................................................7
RS-232 (Male DB9)......................................................................7
RS-422/485....................................................................................8
STATUS PORT......................................................................................8
SPECIFICATIONS....................................................................... 9
ENVIRONMENTAL SPECIFICATIONS.......................................................9
MANUFACTURING................................................................................9
POWER CONSUMPTION........................................................................9
MEAN TIME BETWEEN FAILURES (MTBF)..........................................9
PHYSICAL DIMENSIONS........................................................................9
APPENDIX A -TROUBLESHOOTING....................................... 10
APPENDIX B -HOW TO GET ASSISTANCE............................. 11
APPENDIX C -ELECTRICAL INTERFACE................................ 12
RS-232.............................................................................................12

RS-422.............................................................................................12
RS-485.............................................................................................13
APPENDIX D -PC/104............................................................ 14
WHAT IS PC/104?............................................................................14
APPENDIX E -SILK-SCREEN.................................................. 15
APPENDIX F -SCHEMATIC..................................................... 16
WARRANTY............................................................................ 18
Figures
Figure 1 -Address Selection Table..................................................................2
Figure 2 -Port to Connector Table..................................................................3
Figure 3 -Headers E1, E2, E3, & E4 -IRQ Selection....................................3
Figure 4 -Headers E7 and E8 -RS-485 Enable and Echo Selection.............4
Figure 5 -RS-232 Connector Pin Assignments...............................................7
Figure 6 -RS-422/485 Connector Assignments..............................................8
© 1999i Sealevel Systems, Incorporated. All rights reserved.

Introduction
Sealevel Systems C4-104 Page 1
Introduction
Overview
The Sealevel Systems C4-104 series provides four selectable RS-232 or RS-
422/485 serial I/O ports for your PC/104 application.
What’s Included
The C4-104 is shipped with the following items. If any of these items is
missing or damaged, contact the supplier.
•(1) C4-104 Serial Interface Adapter
•(4) DB-9 Cable Assemblies
•(1) Nylon Hardware Kit
•Serial Utility Software
•User Manual
Factory Default Settings
The C4-104 factory default settings are as follows:
Base Address IRQ
Port 1 280 5
Port 2 288 5
Port 3 290 5
Port 4 298 5
To install the C4-104 using factory default settings, refer to Installation
Operating System Installation
For Windows Users
Start by choosing Install Software at the beginning of the CD. Choose
Asynchronous COM: Port Software,SeaCOM.
Other Operating Systems
Refer to the appropriate section of the Serial Utilities Software.
System Installation on page 6.
For your reference, record installed C4-104 settings below:
Base Address IRQ
Port 1
Port 2
Port 3
Port 4

Card Setup
Sealevel Systems C4-104 Page 2
Card Setup
The C4-104 contains several jumper straps for each port that must be set for
proper operation. Address Selection
The C4-104 occupies four port addresses with each port occupying 8
consecutive I/O locations. A DIP switch (SW1) is used to set the port address
options for the C4-104. Be careful when selecting the port addresses as some
selections may conflict with existing ports. The following table shows the
addressing options available with the standard PAL. If you do not see an address
option that suits your needs, please contact Sealevel Systems Technical
Support about a custom PAL option.
Port1
J1 Port2 J2 Port3 J3 Port4 J4 SW1 1SW1 2SW1 3SW1 4
3F8 2F8 3E8 2E8 On On On On
2F8 3E8 2E8 2E0 On On On Off
3E8 2E8 280 288 On On Off On
280 288 290 298 On On Off Off
2A0 2A8 2B0 2B8 On Off On On
500 508 510 518 On Off On Off
580 588 590 598 On Off Off On
Figure 1-Address Selection Table
DOS Note: Typically COM1: through COM4: addresses are 3F8, 2F8, 3E8
& 2E8 Hex (this is the first addressing option in the above
table). If a COM1: is already present use the second addressing
option, this will provide the typical addresses for COM2:
through COM4: and a fourth port address at 2E0 Hex
XENIX Note: If COM1: is not installed, use base address 500 Hex and IRQ 4
for COM1:. If COM1: is installed, then select base address 580
Hex and IRQ3 (XENIX COM2:)

Card Setup
Sealevel Systems C4-104 Page 3
Port # Connector Location
1J2
2J3
3J4
4J5
Figure 2-Port to Connector Table
IRQ Selection
Headers E1-E4 select the Interrupt Request (IRQ) for each serial port. E1
selects the IRQ selection for Port 1, E2 for Port 2, E3 for Port 3, and E4 for
Port 4. If COM1: is selected, this jumper must be on the IRQ4 setting. If
COM2: is selected, this jumper must be on IRQ3. Consult your particular
software for IRQ selection. If no interrupt is desired, remove the jumper.
E1 E2 E3 E4
2/9
3
4
5
7
10
11
12
15
R
Figure 3-Headers E1, E2, E3, & E4 -IRQ Selection
Position “R” is provided so that you can install a jumper that connects a 1K
ohm pull-down resistor to the output of a high-impedance tri-state driver that
carries the IRQ signal. Because the IRQ line is driven low only by the pull-
down resistor you can have two or more boards which share the same IRQ
signal. Position “R” installed is the default setting and should be left on unless
multiple ports or cards are sharing a single IRQ. If multiple ports or cards are
sharing a single IRQ then only one pull-down resistor is needed in the circuit.

Card Setup
Sealevel Systems C4-104 Page 4
RS-485 Mode (RTS Enable)
E7 & E8 select whether the RS-485 driver is enabled by the UART signal
Request To Send (RTS) or always enabled. With the jumper installed, RTS
enables the RS-485 driver. Removing the jumper enables the driver regardless
of RTS. The jumper should be installed for a 2/4 wire RS-485 application
where the C4-104 is acting as a polled node on a multi-drop network. Remove
the jumper if you are using a point to point RS-422 application such as
Programmable Logic Controllers (PLC's), etc. Half-duplex two-wire operation
is also possible by connecting TX+ to RX+ and TX-to RX-in your cable hood.
To enable the driver with RTS install jumpers at E7-1 for Port 1, E7-3 for Port
2, E8-1 for Port 3 and E8-3 for Port 4. Failure to correctly set this jumper can
cause transmitter contention problems preventing operation by any nodes on
the network.
Note: By connecting the TX+ to the RX+ and TX-to RX-you will experience a
condition termed RS-485 “Echo”. This means that when you transmit a
data character it will be “Echoed” back through the receiver circuit,
presenting itself as a received data character. This can be useful in RS-
485 communications by providing a benchmark for the end of
transmission (i.e. when the amount of received data available equals the
transmit data count). The RS-485 “Echo” can be disabled at E7 and E8.
To disable the echo install a jumper at E7-2 for Port 1, E7-4 for Port 2,
E8-2 for Port 3 and E8-4 for Port 4.
The following example shows the drivers in the RS-485 mode and the echo
enabled.
1 2 3 4
E7-1Port 1 RS-485 Enable
E7-2Port 1 RS-485 Echo Disable
E7-3Port 2 RS-485 Enable
E7-4Port 2 RS-485 Echo Disable
E8-1Port 3 RS-485 Enable
E8-2Port 3 RS-485 Echo Disable
E8-3Port 4 RS-485 Enable
E8-4Port 4 RS-485 Echo Disable
Figure 4-Headers E7 and E8 -RS-485 Enable and Echo Selection

Card Setup
Sealevel Systems C4-104 Page 5
Interface Selection
Due to the versatility of the C4-104, a wide range of interface configuration
options is available to the end user. Please use this section as a guide in
configuring your board to provide the interface you require.
RS-232
1. Remove the 75174 drivers at U1 & U5.
2. Install MAX204 drivers at U2 & U6.
3. Remove all jumpers at E5 and E6.
RS-422/485
1. Install the 75174 drivers at U1 & U5.
2. Remove MAX204 drivers at U2 & U6.
3. Install all jumpers at E5 and E6.
Combined RS-232 & RS-422/485
Please use the following table as a guide in configuring the C4-104 in this
manner.
Configuration Drivers Headers E5 and E6
Ports 1 & 2 RS-232
Ports 3 & 4 RS-422 U1 & U6 Installed U2 & U5 Removed E6 jumpers Removed E5 jumpers Installed
Ports 1 & 2 RS-422
Ports 3 & 4 RS-232 U2 & U6 Installed U1 & U5 Removed E6 jumpers Installed E5 jumpers Removed

Technical Description
Sealevel Systems C4-104 Page 6
Installation
Operating System Installation
For Windows Users
Start by choosing Install Software at the beginning of the CD. Choose
Asynchronous COM: Port Software, SeaCOM.
Other Operating Systems
Refer to the appropriate section of the Serial Utilities Software.
System Installation
Extreme care should be taken when installing the C4-104 to avoid causing
damage to the connectors. After the adapter is installed, connect your I/O
cables to J1-J4. Please note these headers are keyed so that pin 1 of the cable
matches pin 1 of the connector. Refer to Card Setup for information on setting
the address and jumper options before inserting the C4-104 onto the stack.
1. Turn off PC power. Disconnect the power cord.
2. Remove the PC case cover (if applicable).
3. Gently insert the C4-104 connector P1 noting proper key orientation of the
expansion connector on a PC/104 compatible card. The C4-104 adapter is
keyed per the PC/104 Revision 2.1 Specification. This will aid in
preventing the adapter from being inserted incorrectly.
4. Mounting hardware (nylon stand-offs and screws) is provided to insure a
good mechanical connection. Retain any mounting hardware not used to
allow for future expansion.
5. The cables provided are keyed and can be installed before or after the
adapter is inserted in the stack.
6. Replace the cover.
7. Connect the power cord.
Installation is complete.

Technical Description
Sealevel Systems C4-104 Page 7
Technical Description
The C4-104 provides four RS-232 or RS-422/485 serial ports, utilizing a
16554 UART. This chip features programmable baud rates, data format,
interrupt control and a 16-byte input and output FIFO. This UART is essentially
four 16550 compatible UARTs in a 68 pin PLCC package.
Features
•PC/104 compatible “Stack Through” connector for universal mounting.
•5 volt DC operation.
•DB-9P interface cables provided for ease in connecting.
•All mounting hardware provided.
•Supports TD, RD, RTS, CTS signals.
•Compatible with 16550 specific software.
•RS-422 version Part Number: 3520
•RS-232 version Part Number: 3521
•RS-422/232 version Part number: 3522
Connector Pin assignments
RS-232 (Male DB9)
Signal Name Pin #DB9 J1-J4 Mode
GND Ground 5 9
TD Transmit Data 3 5 Output
RTS Request To Send 7 4 Output
RD Receive Data 2 3 Input
CTS Clear To Send 8 6 Input
Figure 5-RS-232 Connector Pin Assignments
Note: These pin assignments meet the EIA/TIA/ANSI-574 DTE for DB-9 type
connectors. These are the only pins that can be connected in your cable
for RS-232. If any other connections are made your data may become
corrupted. If RTS and CTS are not being used terminate them by
connecting the pins together. This will help insure the best performance.

Technical Description
Sealevel Systems C4-104 Page 8
RS-422/485
Signal Name Pin # J1-J4 Mode
TX + Transmit Data Positive 4 7 Output RS-
422
TX-Transmit Data Negative 3 5 Output RS-
422
RTS+ Request To Send Positive 6 2 Output RS-
422
RTS-Request To Send Negative 7 4 Output RS-
422
GND Ground 5 9
RX+ Receive Data Positive 1 1 Input RS-422
RX-Receive Data Negative 2 3 Input RS-422
CTS+ Clear To Send Positive 9 8 Input RS-422
CTS-Clear To Send Negative 8 6 Input RS-422
Figure 6-RS-422/485 Connector Assignments
Status Port
The Sealevel C4-104 also provides the user with an interrupt status port for
greater throughput when servicing multiple ports on a single interrupt line. The
interrupt status port is a read only 8-bit port that sets a corresponding bit when
an interrupt is pending. Port 1 interrupt line corresponds with bit D0 of the
status port, Port 2 with bit D1, Port 3 with bit D2, and Port 4 with bit D3. The
status port allows your system to reduce the amount of polling required to
service up to four ports. Bits D4 through D7 are not driven by the interrupt
status port and can be either a 1 or 0.
The Status Port is located at Base+7 on each port (example: Base=280 Hex,
status port=287, 28F, 297, and 29F Hex. All four status ports on the C4-104
are identical, so any one of the four can be read.
Example: This indicates that Port 2 has an interrupt pending.
Bit Position: 76543210
Value Read: 00000010

Specifications
Sealevel Systems C4-104 Page 9
Specifications
Environmental Specifications
Specification Operating Storage
Temperature Range 0º to 50º C
(32º to 122º F) -20º to 70º C (-4º to 158º F)
Humidity Range 10 to 90% R.H.
Non-Condensing 10 to 90% R.H. Non-Condensing
Manufacturing
•All Sealevel Systems Printed Circuit boards are built to U.L. 94V0 rating
and are 100% electrically tested. These printed circuit boards are solder
mask over bare copper or solder mask over tin nickel.
Power Consumption
Supply line +5 VDC
Rating 130 mA
Mean Time Between Failures (MTBF)
Greater than 150,000 hours. (Calculated)
Physical Dimensions
The C4-104 is PC/104 “Compliant” meaning that it conforms to all
non-optional aspects of the PC/104 Specification including both mechanical
and electrical specifications.
Board Length 3.775 inches (9.588 cm)
Board Width 3.550 inches (9.017 cm)

Appendix A -Troubleshooting
Sealevel Systems C4-104 Page 10
Appendix A -Troubleshooting
Serial Utility test software is supplied with the Sealevel Systems adapter and
will be used in the troubleshooting procedures. By using this software and
following these simple steps, most common problems can be eliminated
without the need to call Technical Support.
1. Identify all I/O adapters currently installed in your system. This includes
your on-board serial ports, controller cards, sound cards etc. The I/O
addresses used by these adapters, as well as the IRQ (if any) should be
identified.
2. Configure your Sealevel Systems adapter so that there is no conflict with
currently installed adapters. No two adapters can occupy the same I/O
address.
3. Make sure the Sealevel Systems adapter is using a unique IRQ The IRQ is
typically selected via an on-board header block. Refer to the section on
Card Setup for help in choosing an I/O address and IRQ.
4. Make sure the Sealevel Systems adapter is securely installed in a
motherboard slot.
5. When running DOS, Windows 3.x or other operating systems refer to the
Serial Utilities software for that operating system and the User Manual to
verify that the Sealevel Systems adapter is configured correctly. The
supplied software contains a diagnostic program 'SSD' that runs under DOS
and will verify if an adapter is configured properly. This diagnostic
program is written with the user in mind and is easy to use. Refer to the
DIAG.txt file in the dos\diag directory for detailed instructions on using
'SSD'.
6. For Windows 95/98 and Windows NT, the diagnostic tool 'WinSSD' is
installed in the Sealevel folder on the Start Menu during the setup process.
First find the ports using the Device Manager, then use 'WinSSD' to verify
that the ports are functional.
Always use the Sealevel Systems diagnostic software when troubleshooting a
problem. This will help eliminate any software issues and identify any hardware
conflicts.

Appendix B -How To Get Assistance
Sealevel Systems C4-104 Page 11
Appendix B -How To Get Assistance
Please refer to Troubleshooting Guide prior to calling Technical Support.
1. Read this manual thoroughly before attempting to install the
adapter in your system.
2. When calling for technical assistance, please have your user
manual and current adapter settings. If possible, please have the
adapter installed in a computer ready to run diagnostics.
3. Sealevel Systems maintains a Home page on the Internet. Our
home page address is www.sealevel.com. The latest software
updates, and newest manuals are available via our FTP site that can
be accessed from our home page.
4. Technical support is available Monday to Friday from 8:00 a.m. to
5:00 p.m. eastern time. Technical support can be reached at (864)
843-4343.
RETURN AUTHORIZATION MUST BE OBTAINED FROM SEALEVEL
SYSTEMS BEFORE RETURNED MERCHANDISE WILL BE ACCEPTED.
AUTHORIZATION CAN BE OBTAINED BY CALLING SEALEVEL
SYSTEMS AND REQUESTING A RETURN MERCHANDISE
AUTHORIZATION (RMA) NUMBER.

Appendix C -Electrical Interface
Sealevel Systems C4-104 Page 12
Appendix C -Electrical Interface
RS-232
Quite possibly the most widely used communication standard is RS-232. This
implementation has been defined and revised several times and is often
referred to as RS-232 or EIA/TIA-232. The IBM PC computer defined the
RS-232 port on a 9 pin D sub connector and subsequently the EIA/TIA approved
this implementation as the EIA/TIA-574 standard. This standard is defined as
the 9-Position Non-Synchronous Interface between Data Terminal
Equipment and Data Circuit-Terminating Equipment Employing Serial
Binary Data Interchange. Both implementations are in wide spread use and
will be referred to as RS-232 in this document. RS-232 is capable of operating
at data rates up to 20 Kbps at distances less than 50 ft. The absolute maximum
data rate may vary due to line conditions and cable lengths. RS-232 often
operates at 38.4 Kbps over very short distances. The voltage levels defined by
RS-232 range from -12 to +12 volts. RS-232 is a single ended or unbalanced
interface, meaning that a single electrical signal is compared to a common
signal (ground) to determine binary logic states. A voltage of +12 volts (usually
+3 to +10 volts) represents a binary 0 (space) and -12 volts (-3to -10 volts)
denotes a binary 1 (mark). The RS-232 and the EIA/TIA-574 specification
defines two type of interface circuits, Data Terminal Equipment (DTE) and
Data Circuit-Terminating Equipment (DCE). The Sealevel Systems adapter is a
DTE interface.
RS-422
The RS-422 specification defines the electrical characteristics of balanced
voltage digital interface circuits. RS-422 is a differential interface that defines
voltage levels and driver / receiver electrical specifications. On a differential
interface, logic levels are defined by the difference in voltage between a pair of
outputs or inputs. In contrast, a single ended interface, for example RS-232,
defines the logic levels as the difference in voltage between a single signal and
a common ground connection. Differential interfaces are typically more
immune to noise or voltage spikes that may occur on the communication lines.
Differential interfaces also have greater drive capabilities that allow for longer
cable lengths. RS-422 is rated up to 10 Megabits per second and can have
cabling 4000 feet long. RS-422 also defines driver and receiver electrical
characteristics that will allow 1 driver and up to 32 receivers on the line at
once. RS-422 signal levels range from 0 to +5 volts. RS-422 does not define a
physical connector.

Appendix C -Electrical Interface
Sealevel Systems C4-104 Page 13
RS-485
RS-485 is backwardly compatible with RS-422; however, it is optimized for
partyline or multi-drop applications. The output of the RS-422/485 driver is
capable of being Active (enabled) or Tri-State (disabled). This capability allows
multiple ports to be connected in a multi-drop bus and selectively polled.
RS-485 allows cable lengths up to 4000 feet and data rates up to 10 Megabits
per second. The signal levels for RS-485 are the same as those defined by
RS-422. RS-485 has electrical characteristics that allow for 32 drivers and 32
receivers to be connected to one line. This interface is ideal for multi-drop or
network environments. RS-485 tri-state driver (not dual-state) will allow the
electrical presence of the driver to be removed from the line. Only one driver
may be active at a time and the other driver(s) must be tri-stated. The output
modem control signal Request to Send (RTS) controls the state of the driver.
Some communication software packages refer to RS-485 as RTS enable or
RTS block mode transfer. RS-485 can be cabled in two ways, two wire and four
wire mode. Two wire mode does not allow for full duplex communication, and
requires that data be transferred in only one direction at a time. For half-duplex
operation, the two transmit pins should be connected to the two receive pins
(Tx+ to Rx+ and Tx-to Rx-). Four wire mode allows full duplex data transfers.
RS-485 does not define a connector pin-out or a set of modem control signals.
RS-485 does not define a physical connector.

Appendix D -PC/104
Sealevel Systems C4-104 Page 14
Appendix D -PC/104
What is PC/104?
The PC has become extremely popular in both general purpose (desktop) and
dedicated (embedded) applications. Unfortunately the PC has been hampered
by the large size required to maintain PC compatibility. PC/104 addresses this
by optimizing the PC bus in a formfactor designed for embedding.
Briefly, the key differences between PC/104 and the standard “AT” or ISA bus
computer are as follows:
•Reducing the form factor, to 3.550 by 3.775 inches
•Eliminating the need for backplanes or card cages, through its self-stacking
bus
•Minimizing component count and power consumption (typically 1-2Watts
per module) by reducing required bus drive on most signals to 4 mA.
Sealevel Systems has been a member of the PC/104 Consortium since its
inception.
Questions about the PC/104 Consortium can be sent to:
PC/104 Consortium
849 Independence Ave., Suite B
Mountain View, CA 94043
[phone] Ph. [phone] Fax
http://www.pc104.org
email: [email protected]

Appendix E -Silk-Screen
Sealevel Systems C4-104 Page 15
Appendix E -Silk-Screen
3.550"
3.775"

Appendix F -Schematic
Sealevel Systems C4-104 Page 16
Appendix F -Schematic
GND
GND
51
RP1:4
1K
41
RP1:3
1K
5 3 7 9
11 13 15 17 19 20
18 16 14 12 10 8 6 4 21
E4 5 3 7 9
11 13 15 17 19 20
18 16 14 12 10 8 6 4 21
E3
21
RP1:1
1K
5 3 7 9
11 13 15 17 19 20
18 16 14 12 10 8 6 4 21
E1
31
RP1:2
1K
5 3 7 9
11 13 15 17 19 20
18 16 14 12 10 8 6 4 21
E2
FOR TRI-STATE IRQ CUT CONNECTION BETWEEN PINS 1 & 2 ON E13 ON BOTTOM SIDE OF BOARD
D2
1N4148
D3
1N4148
+5V
+5V
1N/C 2GND 3
OUT
4
VCC
1.8432 MHz
Y1
21
E9
GND
2
D0
P2
1
C0
P2
40
D19
P2
34
D16
P2
38
D18
P2
2
B1
P1
62
B31
P1
63
A32
P1
64
B32
P1
GND GND GND GND GND GND GND GND
C1
.1uF
10uF
C3
+5V
58
B29
P1
6
B3
P1
D4
1N4148
+5V +5V +5V
C4
.1uF
C5
.1uF
C2
.1uF
C15
.1uF
IRQ15 IRQ12 IRQ11 IRQ10
IRQ5 IRQ7 IRQ4 IRQ3 IRQ9
50
B25
P1
48
B24
P1
46
B23
P1
40
B20
P1
8
B4
P1
10
D4
P2
12
D5
P2
14
D6
P2
8
D3
P2
GND
51
RP2:4
D2 D1 D0 D3 D7 D6 D5
AEN
IOR
RESET
IOW
D4
7
A4
P1
5
A3
P1
4
B2
P1
13
A7
P1
11
A6
P1
17
A9
P1
15
A8
P1
28
B14
P1
21
A11
P1
26
B13
P1
61
A31
P1
9
A5
P1
3
A2
P1
41
RP2:3
21
RP2:1
1K
31
RP2:2
1 8 2 3 4 5
6 7
SW1
41
A21
P1
43
A22
P1
45
A23
P1
47
A24
P1
49
A25
P1
51
A26
P1
53
A27
P1
55
A28
P1
57
A29
P1
59
A30
P1
A10
A5 A6 A7 A8 A9 A0 A1 A2 A3 A4 AEN
A3 A4 A5 A6 A7
E244
A2 A1
+5V
A8 A9 A0 IOR A10
SW1 SW2 SW3 SW4 CS2CS2
CS1 CS3 CS4
D1
1N4148
GND
GND
GND
61
RP1:5
1K
1AEN 2A3 3A4 4A5 5A6 6A7 7A8 20
A1
21
A2
24
VCC 18
E244
8A9 9A10
10 SW1 11 SW2 13 SW3 23 IOR 14 SW4 12 GND
16
CS1
15
CS3
17
CS2
19
A0
22
CS4
U4
22V10-3520
INT1INT1 INT2INT2 INT3INT3 INT4INT4
D7 D5 D6 D0 D1 D2 D3 D4
21
E10
+5V
RESGND
FOR 16C654 CUT CONNECTION BETWEEN PINS 1 & 2 ON E12 ON BOTTOM SIDE OF BOARD
SHEET 3
RX1
CTS1 RTS1
TX1 RX2
CTS2 RTS2
TX2 RX3
SHEET2 SHEET2 SHEET2 SHEET2 SHEET2 SHEET2 SHEET2 SHEET2 SHEET2
E244 INT4 INT3INT3 INT2INT2
1RTS1 2RTS2 3RTS3 4RTS4 5INT1 6INT2 7INT3 8INT4 9E244
10 GND 11
GND
12
D3
13
D2
14
D1
15
D0
16
RTS_EN1
17
RTS_EN2
18
RTS_EN3
19
RTS_EN4
20
VCC
U8
16L8-3520
C16
.1uF
C17
.1uF
GND
CLK
37 RESET 18 IOW 52 IOR 34 A0 33 A1 32 A2 20 CS2 50 CS3 54 CS4
6GND
23GND
40GND
57GND
53
TX3
56
RTS4
58
DTR4 59
CTS4
60
DSR4
61
CD4 62
RI4
63
RX4
35 XTAL1
51
TX3
48
RTS3
46
DTR3
45
CTS3
44
DSR3
43
CD3
42
RI341
RX3
19
TX2 22
RTS2
24
DTR2
25
CTS2 26
DSR2
27
CD2
28
RI2
29
RX2
17
TX1
14
RTS1
12
DTR1
11
CTS1
10
DSR1
9
CD1
8
RI1
7
RX1
13
VCC
30
VCC
47
VCC
64
VCC
36 XTAL2 16 CS1 66 D0 67 D1 68 D2
1D3 2D4 3D5 4D6 5D7
15 INT1 21 INT2 49 INT3 55 INT4 65 INTSEL 31 NC 38 RXRDY 39 TXRDY
16C554
U9
CS3 CS2 CS1
A2 A1 A0 IOR
IOW
RESET
CS4
INT1INT1 RTS1 RTS2 RTS3 RTS4
CTS3 RTS3
TX3 RX4
CTS4 RTS4
TX4
EN4 EN3 EN2 EN1
SHEET2 SHEET2 SHEET2 SHEET2 SHEET2 SHEET2 SHEET2 SHEET2 SHEET2 SHEET2
+5V
D0 D2 D1 D3
SHEET2
GND

Appendix F -Schematic
Sealevel Systems C4-104 Page 17
GND
4T1IN 3T2IN
13 T3IN 14 T4IN
2
T2OUT
16
T3OUT
10 C2+ 11 C2-
8
V+ 6
VCC
7C1+ 9C1-
1
T1OUT
15
T4OUT
12
V- 5
VSS
MAX204
U6
C14
.1 uF
C13
.1 uF
C11
.1 uF
4EN 11A 72A 93A
15 4A 12 EN
8
GND
2
1Y 3 1Z 6 2Y 5 2Z 10 3Y 11 3Z 14 4Y 13 4Z
16
VCC
U5
75174
C10
.1 uF
RTS4
TX4
RTS3
TX3
EN3 EN4
DEN3DEN3 DEN4DEN4 REN3 REN4
SHEET 1 SHEET 1 SHEET 1 SHEET 1 SHEET 1 SHEET 1
+5V
4T1IN 3T2IN
13 T3IN 14 T4IN
2
T2OUT
16
T3OUT
10 C2+ 11 C2-
8
V+
6
VCC
7C1+ 9C1-
1
T1OUT
15
T4OUT
12
V- 5
VSS
MAX204
U2
5 3 7 8
6 4 21
E8
C7
.1 uF
C9
.1 uF
2J4:2 7J4:7 5J4:5 4J4:4 4J3:4 5J3:5 7J3:7 2J3:2
TD3+ TD3-
RTS3+ RTS3-
TD4+ TD4-
RTS4+ RTS4-
GND
+5V
+5V
4.7k
9 8 7 6 5 4 3 2 1
RP6
SHEET 1
RX4
CTS3
RX3
CTS4
SHEET 1 SHEET 1 SHEET 1
8
GND
4EN1 31Y 52Y
11 3Y 13 4Y 12 EN2 2
1A 1 1B 6 2A 7 2B 10 3A 9 3B 14 4A 15 4B
16
VCC
U7
75175
+5V
GND
10 J1:10 10 J2:10 10 J3:10 10 J4:10
C8
.1 uF
4EN 11A 72A 93A
15 4A 12 EN
8
GND
2
1Y 3 1Z 6 2Y 5 2Z 10 3Y 11 3Z 14 4Y 13 4Z
16
VCC
U1
75174 GND
SHEET 1 SHEET 1 SHEET 1 SHEET 1
RTS1
TX1 TX2
RTS2
C6
.1 uF
+5V
SHEET 1 SHEET 1
5 3 7 8
6 4 21
E7
REN2 DEN2 REN1 DEN1
EN2 EN1
+5V
+5V
+5V
5J2:5 4J2:4 7J2:7 2J2:2 7J1:7 4J1:4 5J1:5 2J1:2
TD2- TD1+ TD1-
RTS1+ RTS1-
TD2+
RTS2+ RTS2-
8
GND
4EN1 31Y 52Y
11 3Y 13 4Y 12 EN2 2
1A 1 1B 6 2A 7 2B 10 3A 9 3B 14 4A 15 4B
16
VCC
U3
75175
SHEET 1 SHEET 1 SHEET 1 SHEET 1
CTS2
RX2
CTS1
RX1
4.7k
9 8 7 6 5 4 3 2 1
RP7
GND
2 1
RP8:1
1 K
3 1
RP8:2
1 K
4 1
RP8:3
1 K
5 1
RP8:4
1 K
2 1
RP3:1
1 K
3 1
RP3:2
1 K
4 1
RP3:3
1 K
5 1
RP3:4
1 K
152
RP5:2
100
143
RP5:3
100
134
RP5:4
100
+5V
161
RP5:1
100
21
RP4:1
1K
31
RP4:2
1K
41
RP4:3
1K
51
RP4:4
1K
RD1+ RD1-
1J1:1
CTS2- CTS2+
RD2- RD2+
CTS1- CTS1+
3J1:3 6J1:6 9J1:9 8J1:8 3J2:3 1J2:1 6J2:6 8J2:8 9J2:9
GND
5 3 7 8
6 4 21
E5
GND
6 1
RP8:5
1 K
9 1
RP3:8
1 K
8 1
RP3:7
1 K
7 1
RP3:6
1 K
6 1
RP3:5
1 K
98
RP5:8
100
5 3 7 8
6 4 21
E6
GND
125
RP5:5
100
116
RP5:6
100
107
RP5:7
100
61
RP4:5
1K
71
RP4:6
1K
81
RP4:7
1K
91
RP4:8
1K
RD3+ RD3-
CTS3+ CTS3-
RD4+ RD4-
CTS4+
3J3:3 1J3:1 6J3:6 9J3:9 8J3:8 1J4:1 3J4:3 9J4:9
GND
CTS4-
6J4:6 8J4:8