Optoelectronics Scout serial interface specification v.1.1

Optoelectronics, Inc.

Scout

Serial Interface Specification

Interface Version 1.1

March 22, 1995

INTRODUCTION

This document describes the serial interface of the Scout, a miniature hand-held frequency counter capable of
measuring the frequency of VHF and UHF transmitters and other signal sources. The Scout has special features
which make it invaluable for radio surveillance work. In particular, the Scout is capable of automatically
capturing and storing up to 400 frequencies, along with the number of occurrences, or count, of each frequency.
This frequency data can then be downloaded to a personal computer for logging and analysis. In addition, the
Scout can be connected to a scanning receiver, such as the Realistic PRO-2006 or PRO-2005 receiver equipped
with an OptoScan456 board, to automatically tune the receiver to captured frequencies in real time. In this
configuration, frequencies captured by the Scout can be monitored immediately.

This document was written to assist the programmer in developing software applications for the Scout.

Optoelectronics, Inc. assumes no responsibility for the accuracy of the information contained in this document.
Optoelectronics, Inc. is under no obligation to provide technical support on matters pertaining to this document, or
to provide notification of changes or corrections to this document. To inquire about possible revisions, or to order
copies of this document, contact the factory. A nominal fee may be charged to cover printing and shipping costs.

OPTOELECTRONICS, INC.

5821 N.E. 14th Avenue

Fort Lauderdale, FL 33334

Phone: [phone]

FAX: [phone]

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ABOUT CI-V

The serial interface on the Scout conforms to the Icom CI-V interface standard. The CI-V interface is an
asynchronous, half-duplex, Transistor Transistor Logic (TTL) serial interface connected in a wire-OR (bussed)
configuration. Several different devices can be connected to the bus simultaneously, and each device has its own
unique address. Software developers are strongly encouraged to obtain a copy of the Icom Communication
Interface - V Reference Manual from Icom, Inc. for detailed information on the CI-V interface protocol. The
communications parameters for the serial interface are listed in Table 1 below.

Table 1. Communications Parameters.

DATA RATE
START BITS
DATA BITS
PARITY
STOP BITS

One important thing to note about the CI-V interface is that, as mentioned above, it is connected in a wire-OR
configuration. This means that the transmit data signal and the receive data signal are connected together.
Therefore, when a command is transmitted by the computer, it is automatically echoed back as received data,
followed by the response to the command, if any. For example, if an eleven-byte command is transmitted to a
device on the bus, which returns a six-byte response, the computer will receive a total of seventeen bytes. This
configuration allows devices on the bus to monitor their own transmissions in order to detect interface collisions.
A collision occurs when two or more devices transmit simultaneously. If a collision occurs, the command must be
re-transmitted.

9600 bps
1
8
NONE
1

To connect the Scout to a computer, a subminiature phone jack is provided on the top panel. An external
interface converter box, such as the Optoelectronics model CX12 or Icom model CT-17, is required to connect the
Scout to an RS-232C computer interface. Its purpose is to convert the CI-V interface voltage levels to RS-232C
levels compatible with most personal computers.

CI-V ADDRESS JUMPER SETTINGS

There are two jumpers located on the Scout circuit board which are used to select the CI-V interface address.
Four different addresses are available, making it possible for up to four Scout units to be connected to a CI-V
interface bus. In order to communicate with the Scout, the computer software must specify the address selected
by the two jumpers. The CI-V address jumper settings are listed in Table 2 below. All addresses are specified in
hexadecimal notation. The factory default setting, address 90, is shown in bold type.

Table 2. CI-V Address Jumper Settings.

U2 PIN 6 U2 PIN 7 ADDRESS

OPEN OPEN 90

SHORT OPEN 91

OPEN SHORT 92

SHORT SHORT 93

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COMMAND REFERENCE

As mentioned earlier, the Scout conforms to the Icom CI-V interface standard. In this section, all CI-V
command and response bytes are expressed in hexadecimal notation.

When NORMAL mode is selected, the Scout recognizes eight different commands. The commands, along with
their corresponding responses, are summarized in Table 3 below. The Scout only responds to commands when
NORMAL mode is selected (CAPTURE and RECALL switches both in the OFF position). In all other modes, the
Scout automatically tunes a receiver connected to the CI-V interface, and, therefore, can accept no commands.

Following the table is a detailed description of each of the commands, including examples illustrating their use. In
the command descriptions, "ra" refers to the RECEIVE ADDRESS, and "ta" refers to the TRANSMIT ADDRESS.

The RECEIVE ADDRESS is the address of the Scout. The two address jumpers are used to select any address in
the range 90 through 93. Each device on the CI-V bus must have its own unique address. The Scout will not
process any command in which the RECEIVE ADDRESS does not match the address selected by the address
jumpers. However, the Scout will process commands with a RECEIVE ADDRESS of 00, but all command
responses will be suppressed. A RECEIVE ADDRESS of 00 has special meaning. It provides a means for a
device on the CI-V bus to transmit a command to all other devices simultaneously. However, since several
simultaneous responses would cause a collision, the responses are suppressed.

The TRANSMIT ADDRESS is the address of the device which is transmitting the command to the Scout. In
most cases, this device is a personal computer executing application software, usually referred to as the
CONTROLLER. The standard address for the CONTROLLER is E0, but any address can be used for the
TRANSMIT ADDRESS. However, the TRANSMIT ADDRESS must be in the range 01 to EF. Also, the Scout
will not process any command in which the TRANSMIT ADDRESS matches its own address selected by the
address jumpers.

Table 3. Scout CI-V Interface Command Summary.

COMMAND SUB-COMMAND DESCRIPTION

03 - Read frequency.
15 02 Read signal strength.
7F 09 Read identification
7F 20 Read gate setting.
7F 21 Write gate setting.
7F 22 Read frequency memory.
7F 23 Read count memory.
7F 24 Clear memory.

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