SeaLevel Relio R2 SYNC User manual

1
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
Relio R2 SYNC
User Manual | RELIO R2 SYNC

2
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
Contents
CONTENTS....................................................................................................................................................................................................................................2
INTRODUCTION...........................................................................................................................................................................................................................3
FEATURES.....................................................................................................................................................................................................................................4
COM EXPRESS MODULE/RAM CONFIGURATION OPTIONS ..........................................................................................................4
BEFORE YOU GET STARTED .....................................................................................................................................................................................................5
WHAT’S INCLUDED ...............................................................................................................................................................5
ADVISORY CONVENTIONS.......................................................................................................................................................5
OPTIONAL ITEMS..................................................................................................................................................................6
SPECIFICATIONS ........................................................................................................................................................................................................................8
MECHANICAL DIMENSIONS ....................................................................................................................................................8
ENVIRONMENTAL SPECIFICATIONS ...........................................................................................................................................8
OPERATING TEMPERATURE RANGE ..........................................................................................................................................8
POWER SUPPLY....................................................................................................................................................................9
POWER INPUT .....................................................................................................................................................................9
MANUFACTURING ..............................................................................................................................................................10
SYSTEM OPERATION.................................................................................................................................................................................................................11
POWER BUTTON ................................................................................................................................................................11
POWER STATES..................................................................................................................................................................11
SYNCHRONOUS SERIAL COMMUNICATION PORTS .....................................................................................................................11
INTERNAL BAUD RATE GENERATOR........................................................................................................................................11
CONTROL AND STATUS REGISTERS DEFINITION.........................................................................................................................12
INTERFACE SELECTION .........................................................................................................................................................13
100-PIN CONNECTOR PIN OUT ............................................................................................................................................13
DB-25M CONNECTOR PIN OUTS..........................................................................................................................................15
CMOS BATTERY ................................................................................................................................................................20
SYSTEM DESCRIPTION............................................................................................................................................................................................................20
FRONT PANEL I/O CONNECTORS...........................................................................................................................................20
REAR PANEL I/O CONNECTORS.............................................................................................................................................21
MECHANICAL DRAWINGS.....................................................................................................................................................22
GETTING STARTED ................................................................................................................................................................................................................... 27
WHERE TO GET SOFTWARE ..................................................................................................................................................27
BIOS CONSIDERATIONS .........................................................................................................................................................................................................28
APPENDIX A –HANDLING INSTRUCTIONS ........................................................................................................................................................................29
APPENDIX B –ELECTRICAL INTERFACE..............................................................................................................................................................................30
APPENDIX C –ASYNCHRONOUS COMMUNICATIONS ....................................................................................................................................................31
WARRANTY................................................................................................................................................................................................................................32

3
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
Introduction
Overview
The Relio R2 SYNC is an exceptionally rugged embedded controller with integrated synchronous
communications ports for operating in harsh environments. The R2 SYNC’s fan less and cableless structure
ensures extensive durability for long-term usage. The R2 SYNC differs from traditional industrial computer
systems in that it is built using the PICMG COM Express architecture. Sealevel has partnered with the leading
COM Express module manufacturers to ensure our customers benefit from the best in the industry. This
manual will focus on the higher-level features of the R2 SYNC computer system.
The R2 SYNC is compatible with Basic and Compact form factor Type 6 pin out COM Express modules. COM
Express is a widely supported implementation of Computer on Module (COM) design. The COM Express
architecture reduces the complexity, cost and time required for custom computer system design by combining
the processing, memory, video, Ethernet, and USB functionality in a small, highly integrated module. COM
Express modules install on a carrier board that provides the application specific I/O and external connectors
best suited for the system requirements.
Sealevel COM Express carrier boards leverage the company’s years as a leader in I/O and communication
products to provide carrier board and full system solutions in the fastest time possible. Common I/O features
include serial, analog and digital I/O. Sealevel’s extensive library of proven I/O circuits can be included as
required to meet the specific I/O count, voltage ranges, and connector types.
The R2 SYNC is equipped with a four-port RS-232, RS-422, RS-485,EIA-530, EIA-530A, V.35 synchronous serial
interface. Designed using the popular Zilog Z85230 Enhanced Serial Communication Controller (ESCC), the
board is an ideal solution for military, satellite, radar, banking, and other applications that require robust
synchronous communications.
For maximum flexibility, each of the serial ports can be individually configured for RS-232, RS-422, RS-485,EIA-
530, EIA-530A, V.35 communications. In RS-232 mode, all common modem control signals are implemented
for compatibility with a wide range of peripherals. A digital phase lock loop (DPLL) is included on each port,
and the board supports data rates up to 128K bps in burst mode. For easy implementation, a fan-out cable is
included that terminates the onboard 100-pin connector to four DB-25M connectors.
Software support, critical for successful synchronous communication development, is provided through
Sealevel’s SeaMAC driver. HDLC/SDLC protocols are supported as well as certain configurations of Monosync,
Bi-sync, and Raw modes.
The R2 SYNC also utilizes the Exar SP-506 multi-protocol electrical interface chip that allows it to be compliant
with EIA/TIA-530/530A, EIA/TIA-232E, EIA/TIA 485, and ITU V.35. Optional cables are available to connect RS-
449, RS-530, RS-530A, V.35 and X.21 interfaces.

4
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
Features
The following features are included and installed on the Relio R2 SYNC models.
▪4 Synchronous Serial ports individually configurable for RS-232, RS-422, RS-485, RS-530, RS-530A,
V.35 (DB100 + Cable for 4 DB25 connectors) using the Z85230 Enhanced Serial Communications
Controller (ESCC)
oData rates to 128K bps (Burst mode)
oAll modem control signals implemented
oCompatible with Sealevel 5402 and 5402e Synchronous cards
▪1 Display Port Compatible Video Output
▪2 Gigabit Ethernet Ports
▪2 USB 2.0 Ports
▪64GB mSATA Solid State Drive
▪Power Button with integrated LED
▪Supports Wake-on-LAN
▪18-36 VDC Input
COM Express Module/RAM Configuration options
Part Number
COM Express Module
COM Express Module Description
RAM
R23008-01
IBR-i3-3217UE
Type 6 Standard Module with Intel
Core i3 3217UE Ivy Bridge CPU
8GB DDR3 1333 ECC
R27008-01
IBR-i7-3517UE
Type 6 Standard Module with Intel
Core i7 3517UE Ivy Bridge CPU
8GB DDR3 1333 ECC

5
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
Before You Get Started
What’s Included
The R2 SYNC is shipped with the following items. If any of these items are missing or damaged, please
contact Sealevel at 864.843.4343 for a replacement.
•R2 SYNC Computer System
•BK1042 (Wall mount brackets)
•CA339 Molex 100-Pin to (4) DB25 Male Cable, 36-inch Length
•TR145-US AC/DC Power Supply –Desktop 90-264VAC/47-63Hz 21VDC regulated 3000mA
output with a KPPX-4P connector
Advisory Conventions
Warning
The highest level of importance used to stress a condition where damage could result to the product,
or the user could suffer serious injury.
Important
The middle level of importance used to highlight information that might not seem obvious or a
situation that could cause the product to fail.
Note
The lowest level of importance used to provide background information, additional tips, or other non-
critical facts that will not affect the use of the product.

6
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
Optional Items
Depending upon your application, you are likely to find one or more of the following items useful with the R2
SYNC. All items can be purchased from our website (www.sealevel.com)or by calling our sales team at
[phone].
Cables
CAT5 Patch Cable, 7’ In Length (Part# CA246)
Standard 7' CAT5 Unshielded Twisted Ethernet Pair Patch Cable
(RJ45) with blue jacket.
CAT5 Patch Cable, 10' In Length (Part# CA247)
Standard 10’ CAT5 Unshielded Twisted Pair Ethernet Patch Cable
(RJ45) with blue jacket.
DB25 Female to DB25 Male Extension Cable, 72 inch Length (Item# CA104)
The CA104 is a standard DB25F to DB25M serial extension
cable. Extend a DB25 cable or locate a piece of hardware
where it is needed with this six foot (72 inch) cable. The
connectors are pinned one-to-one so the cable is compatible
with any device or cable with DB25 connectors. The cable is
fully shielded against interference and the connectors are
molded to provide strain relief. Dual metal thumbscrews
secure the cable connections and prevent accidental
disconnection. Recommended for applications with data
rates less than 1M bps.
DB25 Female (RS-530) to DB37 Male (RS-449 DTE) Cable, 10 inch Length (Item#
CA107)
DB25 Female (RS-530) to DB37 Male (RS-449 DTE) Cable, 10
inch Length. RS-530 was designed to replace the bulky DB37
RS-449 connector. The CA107 cable allows any Sealevel RS-
530 adapter to be used in an RS-449 application.

7
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
OPTIONAL ITEMS, CONTINUED
DB25 Female (RS-530) to DB15 Male (X.21) Cable, 72 inch Length (Item# CA159)
DB25 Female (RS-530) to DB15 Male (X.21) Cable, 72 inch
Length. Converts the Standard DB25 implementation of RS-
530 or RS-422 to the ITU-T X.21 standard pinout.
DB25 Female to DB25 Male (RS-530) Twisted Pair Serial Cable, 72 inch Length (Item#
CA174)
DB25 Female to DB25 Male Twisted Pair Serial Cable, 72
inch Length. Twisted Pairs provide increased data integrity in
high-speed serial applications. Recommended for RS-530
applications with data rates greater than 1M bps.
DB25 Female (V.35) to ITU-T ISO-2593 Style Connector (V.35) Cable, 72 inch Length
(Item# CA178)
DB25 Female (V.35) to ITU-T ISO-2593 Style Connector
(V.35) Cable, 72 inch Length. The CA178 converts the
Sealevel DB25 implementation of V.35 to the ITU-T V.35
mechanical standard.

8
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
Specifications
Mechanical Dimensions
Package Length
7.820 inches (19.86 cm)
Package Width1
4.744 inches (12.04 cm)
Package Height
2.672 inches (6.90 cm)
Environmental Specifications
Specification
Operating
Storage
Temperature Range
0º to 50º C (32 º to 122 ºF)1
-40 to 85 ºC (-40 to 185 ºF)
Humidity Range
10 to 90% R.H. Non-Condensing
10 to 90% R.H. Non-Condensing
Operating Temperature Range
The R2 SYNC7008 can operate with no airflow at 50C as long as the steady-state CPU usage does not exceed
50%. If CPU usage is sustained at a workload greater than 50%, the CPU will throttle itself back to keep its
internal temperature in a safe range.
If the application environment requires the computer to operate at 50C with steady state CPU usage greater
than 50%, some additional cooling must be used to ensure safe operation of the electronics.
The R2 SYNC computer system is a fan-less, solid state computer that relies on thermal conduction to move
heat from internal components to the outside of the enclosure. The lid is designed as a finned heat sink to
increase overall surface area. Three main cooling methods can be used to optimize removal of heat from the
system.
1. Airflow
2. Thermal conduction through mounting
3. Computer orientation
1
Width listed is for computer without mounting brackets. Total width with brackets is shown in drawings.
2 Operating temperature is dependent on particular model. See the Operating Temperature Range section for model
capabilities.
Part Number
COM Express Module
Operating Temperature
Range
Comment
R23008-01
IBR-i3-3217UE
0 - 50 °C
Requires Industrial Temperature SSD
R27008-01
IBR-i7-3517UE
0 - 50 °C
Requires Industrial Temperature SSD

9
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
SPECIFICATIONS, CONTINUED
Airflow over the lid provides the most effective heat removal of these three options. It is optimal to mount the
computer in an area that has either natural or forced airflow to constantly remove heat from the enclosure.
Mounting the computer to a large thermally conductive surface (such as an I-Beam, steel cabinet or other large
metal surface) allows heat to travel through the enclosure and be dissipated into the large structure.
Power Supply
The power supply provided has a universal AC input. It provides 21 VDC @ 3.0 A max output to the R2 SYNC
system. Typical power consumption varies depending on COM Express Module, memory capacity,
OS/software activity and peripheral devices. AC current draw will never exceed 1.4 A.
All necessary system voltages are generated from a single DC input capable of accepting 18 VDC to 36 VDC
(fed by above DC power supply).
Acceptable System Input Voltage
18 VDC-36 VDC
DC Current Rating (Dependent on COM Express
Module , input voltage and load)
375 mA-2150 mA
Power Input
The 12003 carrier board is designed to operate from 18VDC up to 36VDC. The current draw varies across this
range and is heavily dependent on the COM Express module, peripheral devices, and installed software. The
connector at J9 is Kycon KPJX-4S. Use Kycon KPPX-4P as the mate if creating your own power cable.
Figure 1 - Power Connector

10
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
SPECIFICATION, CONTINUED
Pin #
Signal
Name
1
+
Positive DC Power
2
-
Negative DC Power (GND)
3
-
Negative DC Power (GND)
4
+
Positive DC Power
Manufacturing
All Sealevel Systems printed circuit boards are built to UL 94V0 rating and are 100% electrically tested.
These printed circuit boards are solder mask over electroless Ni / Immersion gold.

11
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
System Operation
Power Button
The power button on the front of the computer can be used to turn the system on, shut the system down or
place the computer in sleep states S3 or S4 (depending on OS support and configuration). The power button
can also wake the system up from sleep states S3 or S4.
The power button has a 3 second hardware debounce/delay built in so accidental shutdown does not occur.
This 3 second delay is present at all times so the power button must be held for 3 seconds before system
power up, power down, sleep or wake occurs.
Power States
The R2 SYNC is designed to operate in four Power States as defined by ACPI.
S0 –Fully powered and operational
S3 –Suspended to memory (known as sleep in Windows)
S4 –Suspended to disk (known as Hibernate in Windows)
S5 –Powered down in standby (Windows Shutdown)
The system can transition from S0 to any of the three listed standby states (S3, S4, or S5) by either software
command or the Power Button. The system can then be awoken from either listed sleep/standby state by
holding the Power Button for 3 seconds. The system can also be awoken from S3 or S4 with a USB input device
such as a HID compliant keyboard or mouse.
To be awoken from a standby state with a USB device, the device must be present when the
computer enters the sleep state and must remain connected for the duration of the sleep state.
These power states are supported by Windows 8, Windows 7, Windows Vista, and Windows XP.
Synchronous Serial Communication Ports
The R2 SYNC utilizes the Zilog Z85230 Enhanced Serial Communications Controller (ESCC) and includes a
dedicated Z85230 per port. This chip features programmable baud rate, data format and interrupt control.
Refer to the ESCC User Manual, available from Zilog, for details on programming the 85230 ESCC chip in the
event you are writing your own driver as opposed to using the SeaMAC driver.
Internal Baud Rate Generator
The baud rate of the ESCC is programmed under software control. The standard oscillator supplied with the
board is 7.3728 MHz. However, other oscillator values can be substituted to achieve different baud rates. It
should be noted that the Z85230 chip is manufactured in different speed ranges and installation of a different
oscillator may also require changing the Z85230.

12
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
Control and Status Registers Definition
The control and status registers occupy 16 consecutive I/O locations. The following tables provide a
functional description of the bit positions. This table is provided for users that desire to write their own
driver.
X = do not care.
Base
Mode
D7
D6
D5
D4
D3
D2
D1
D0
+4
RD
0
IRQST
0
0
0
0
0
DSRA
+5
RD
485CLK
ECHOA
SYNCA_RTS
SYNCA_CTS
AM3
AM2
AM1
AM0
+5
WR
485CLK
ECHOA
SYNCA_RTS
SYNCA_CTS
AM3
AM2
AM1
AM0
+6
RD
0
0
0
0
RLA
LLA
TSETSLA
RXCOPTA
+6
WR
X
X
X
X
RLA
LLA
TSETSLA
RXCOPTA
+7
RD
X
X
X
X
IRQST4
IRQST3
IRQST2
IRQST1
+14
RD
SD7
SD6
SD5
SD4
SD3
SD2
SD1
SD0
+15
RD
SD15
SD14
SD13
SD12
SD11
SD10
SD9
SD8
Field
Description
IRQST
SCC interrupt status:
1 = No interrupt pending on ESCC
0 = Interrupt pending on ESCC.
DSRA
DSRA:
1 = DSRA not active
0 = DSRA active
LLA
Local Loopback:
1 = LL set
0 = LL not set
RLA
Remote Loopback:
1 = RL set
0 = RL not set
TSETSLA
TSET clock source:
1= Received TXC as source
0 = TRXCA as source
RXCOPTA
RXCOPTA:
1= Selects SCC PCLK for RTXCA
0 = Selects received RXC for
RTXCA
SYNCA_RTS
SYNCA _RTS:
1 = SYNCA connected to RTS
0 = SYNCA is high
SYNCA_CTS
SYNCA_CTS:
1 = SYNCA connected to CTS
0 = SYNCA is high
485CLK
TSET switches with
TXD:
1 = clk switches
0 = no CLK switching
ECHOA
ECHO enable:
1 = echo disabled
0 = echo enabled
AM0 –AM3
I/O mode select. See table for valid interface options.
0 = High Impedance
SD0 –SD15
Optional security feature. Unique value per customer or
application.
Default value = FFFF

13
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
Interface Selection
The R2 SYNC supports a variety of electrical interfaces. Refer to the Control and Status Register Definitions
found in the Technical Description section of this manual for this bit description. There is line termination on
RXD, RXC and TXC in the following modes: RS-530, RS-530A, RS-485T and V.35. This table is provided for
users that desire to write their own driver. By default, at power-up, all signals are high impedance.
HEX
M3
M2
M1
M0
Interface Mode
0
0
0
0
0
All signals are high impedance
1
0
0
0
1
* not supported *
2
0
0
1
0
RS-232
3
0
0
1
1
* not supported *
4
0
1
0
0
RS-485T with 120termination
5
0
1
0
1
RS-485 without termination
6,7,8,9
0
1
1
0
* not supported *
A
1
0
1
0
single ended loopback
B
1
0
1
1
differential loopback
C
1
1
0
0
* not supported *
D
1
1
0
1
RS-530
E
1
1
1
0
V.35
F
1
1
1
1
RS-530A
100-Pin Connector Pin Out
The R2 SYNC has a 100-pin high-density connector and includes a cable (Item# CA339) that breaks out to four
(4) DB25 male connectors. The pin outs for RS-232, RS-485, RS-530, RS-530A and V.35 interfaces on the DB25
connectors are listed on the following pages. For customers designing their own cable, the mating 100-pin
connector is AMP Part# 5787169-9. The pin out for the 100-pin connector is listed below.

14
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
100-Pin Connector
Signal Name
DB25
Port 1
Port 2
Port 3
Port 4
N/C
1
51
26
76
GND
7
2
52
27
77
TXD-
2
3
53
28
78
TXD+
14
4
54
29
79
RTS-
4
5
55
30
80
RTS+
19
6
56
31
81
DTR-
20
7
57
32
82
DTR+
23
8
58
33
83
TSET-
24
9
59
34
84
TSET+
11
10
60
35
85
RXD-
3
11
61
36
86
RXD+
16
12
62
37
87
CTS-
5
13
63
38
88
CTS+
13
14
64
39
89
DSR-
6
15
65
40
90
DSR+
22
16
66
41
91
DCD-
8
17
67
42
92
DCD+
10
18
68
43
93
TXC-
15
19
69
44
94
TXC+
12
20
70
45
95
RXC-
17
21
71
46
96
RXC+
9
22
72
47
97
LL-
18
23
73
48
98
RL-
21
24
74
49
99
NC
25
75
50
100
SHIELD
Shell
Shell
Shell
Shell
Shell

15
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
DB-25M Connector Pin Outs
RS-232 Signals
Base+5, M3-M0=2, 0010
Pin #
Signal
Name
Mode
2
TD
Transmit Data
Output
3
RD
Receive Data
Input
4
RTS
Request To Send
Output
5
CTS
Clear To Send
Input
6
DSR
Data Set Ready
Input
7
GND
Ground
8
DCD
Data Carrier Detect
Input
15
TXC
Transmit Clock
Input
17
RXC
Receive Clock
Input
18
LL
Local Loopback
Output
20
DTR
Data Terminal Ready
Output
21
RL
Remote Loopback
Output
24
TSET
Transmit Signal Element Timing
Output

16
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
RS-485 or RS-485T
Base+5, M3-M0=4, 0100 (With termination)
Base+5, M3-M0=5, 0101 (Without termination)
Pin #
Signal
Name
Mode
2
TDA TX–
Transmit Negative
Output
3
RDA RX–
Receive Negative
Input
7
GND
Ground
9
RXCB RXC+
Receive Clock Positive
Input
11
TSETB TSET+
Transmit Signal Element Timing +
Output
12
TXCB TXC+
Transmit Clock Positive
Input
14
TDB TX+
Transmit Positive
Output
15
TXCA TXC–
Transmit Clock Negative
Input
16
RDB RX+
Receive Positive
Input
17
RXCA RXC–
Receive Clock Negative
Input
24
TSETA TSET–
Transmit Signal Element Timing –
Output

17
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
RS-530 (RS-422)
Base+5, M3-M0=D, 1101
Pin #
Signal
Name
Mode
2
TDA TX–
Transmit Negative
Output
3
RDA RX–
Receive Negative
Input
4
RTSA RTS–
Request To Send Negative
Output
5
CTSA CTS–
Clear To Send Negative
Input
6
DSRA DSR–
Data Set Ready Negative
Input
7
GND
Ground
8
DCDA DCD–
Data Carrier Detect Negative
Input
9
RXCB RXC+
Receive Clock Positive
Input
10
DCDB DCD+
Data Carrier Detect Positive
Input
11
TSETB TSET+
Transmit Signal Element Timing +
Output
12
TXCB TXC+
Transmit Clock Positive
Input
13
CTSB CTS+
Clear To Send Positive
Input
14
TDB TX+
Transmit Positive
Output
15
TXCA TXC–
Transmit Clock Negative
Input
16
RDB RX+
Receive Positive
Input
17
RXCA RXC–
Receive Clock Negative
Input
18
LL
Local Loopback
Output
19
RTSB RTS+
Request To Send Positive
Output
20
DTRA DTR–
Data Terminal Ready Negative
Output
21
RL
Remote Loopback
Output
22
DSRB DSR+
Data Set Ready Positive
Input
23
DTRB DTR+
Data Terminal Ready Positive
Output
24
TSETA TSET–
Transmit Signal Element Timing –
Output

18
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
RS-530A
Base+5, M3-M0=F, 1111
Pin #
Signal
Name
Mode
2
TDA TX–
Transmit Negative
Output
3
RDA RX–
Receive Negative
Input
4
RTSA RTS–
Request To Send Negative
Output
5
CTSA CTS–
Clear To Send Negative
Input
6
DSRA DSR–
Data Set Ready Negative
Input
7
GND
Ground
8
DCDA DCD–
Data Carrier Detect Negative
Input
9
RXCB RXC+
Receive Clock Positive
Input
11
TSETB TSET+
Transmit Signal Element Timing +
Output
12
TXCB TXC+
Transmit Clock Positive
Input
13
CTSB CTS+
Clear To Send Positive
Input
14
TDB TX+
Transmit Positive
Output
15
TXCA TXC–
Transmit Clock Negative
Input
16
RDB RX+
Receive Positive
Input
17
RXCA RXC–
Receive Clock Negative
Input
18
LL
Local Loopback
Output
19
RTSB RTS+
Request To Send Positive
Output
20
DTRA DTR–
Data Terminal Ready Negative
Output
21
RL
Remote Loopback
Output
24
TSETA TSET–
Transmit Signal Element Timing –
Output

19
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
V.35 SIGNALS
Base+5, M3-M0=F, 1111
Pin #
Signal
Name
V.35
Mode
2
TDA TX–
Transmit Negative
P
Output
3
RDA RX–
Receive Negative
R
Input
4
RTS
Request To Send
C
Output *
5
CTS
Clear To Send
D
Input *
6
DSR
Data Set Ready
E
Input *
7
GND
Ground
B
8
DCD
Data Carrier Detect
F
Input *
9
RXCB RXC+
Receive Clock Positive
X
Input
11
TSETB TSET+
Transmit Signal Element Timing +
W
Output
12
TXCB TXC+
Transmit Clock Positive
AA
Input
14
TDB TX+
Transmit Positive
S
Output
15
TXCA TXC–
Transmit Clock Negative
Y
Input
16
RDB RX+
Receive Positive
T
Input
17
RXCA RXC–
Receive Clock Negative
V
Input
18
LL
Local Loopback
Output *
20
DTR
Data Terminal Ready
H
Output *
21
RL
Remote Loopback
Output *
24
TSETA TSET–
Transmit Signal Element Timing –
U
Output
All modem control signals are single-ended (un-balanced) with RS-232 signal levels.

20
© Sealevel Systems, Inc. RELIO R2 SYNC Manual | SL9255 10/2021
CMOS Battery
The R2 SYNC includes a 3V DC type CR2032 battery that supplies the RTC and CMOS memory of the COM
Express CPU module.
Danger of explosion if battery is incorrectly replaced –Replace only with the same or equivalent type
recommended by the manufacturer. Dispose of used batteries according to the manufacturer’s
instructions.
To fulfill the requirements of EN 60950, the R2 SYNC incorporates two current-limiting devices (resistor and
diode) in the battery power supply path.
System Description
The following I/O connectors use industry standard pin outs for maximum compatibility.
Front Panel I/O Connectors