Westbay Technologies WJT844 1000M User Manual

西港机电科技(上海)有限公司

900 MHz TRANSCEIVERS

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WJT844-1000M

User’s Manual

Version 1.0

Westbay Technologies Ltd.

西港机电科技(上海)有限公司

电话/Tel: [phone]
传真/Fax: [phone]
邮箱/E-mail: [e-mail]

上海市浦东新区海桐路 336 弄 1 号楼 701 室

Room 701, Building 1, Lane 336
Haitong Road, Shanghai, China 201204

WJT844-1000M Features

 Two generic input and output digital lines and integrated DAC/ADC functions
 Cost Effective for high volume applications
 Retries and Acknowledgements
 Continuous 76.8 kbps RF data stream
 Software selectable interface baud rates from 1200 bps to 115.2 kbps
 Very low power consumption for battery powered implementations
 Small size for portable and enclosed applications
 Very Low latency and high throughput
 All modules are qualified for Industrial temperatures (-40°C to 80°C)

1. Overview

The WJT844-1000M is a member of Westbay’s ConnexRF OEM transceiver family. The
WJT844-1000M is designed for integration into OEM systems operating under FCC part 15
regulations for the 900 MHz ISM band.

The WJT844-1000M is a cost-effective, high performance. It provides an asynchronous TTL level
serial interface for OEM Host communications. Communications include both system and
configuration data. The Host supplies system data for transmission to other Host(s). Configuration
data is stored in an on-board EEPROM. Synchronization, and RF system data
transmission/reception is performed by the transceiver.

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These transceivers can be used as a direct serial cable replacement – requiring no special Host
software for operation. They also feature a number of On-the-Fly Control Commands providing the
OEM with a very versatile interface for any network.

WJT844-1000M transceivers operate in a Point-to-Point or Point-to-Multipoint, Client-Server. One
transceiver is configured as a Server and there can be one or many Client s.

This document contains information about the hardware and software interface between an
Westbay WJT844-1000M transceiver and an OEM Host. Information includes the theory of
operation, specifications, interface definition, configuration information and mechanical drawings.

西港机电科技(上海)有限公司

电话/Tel: [phone]
传真/Fax: [phone]
邮箱/E-mail: [e-mail]

上海市浦东新区海桐路 336 弄 1 号楼 701 室

Room 701, Building 1, Lane 336
Haitong Road, Shanghai, China 201204

2. WJT844-1000M Specifications

GENERAL

20 Pin Interface Connector
RF Connector MMCX receptacle, mates with any manufacturer’s MMCX style plug

Antenna MMCX Connector
Serial Interface Data Rate Baud rates from 1200 bps to 115,200 bps
Power Consumption (typical)

Security One byte System ID. 56 bit DES encryption key.
Interface Buffer Size Input/Output: 256 bytes each

Frequency Band 902 – 928 MHz
RF Data Rate 76.8kbps fixed
RF Technology FSK
Output Power -4db typica(Conducted 2dBi gain antenna)l
Supply Voltage Pin 10: 3.3 – 5.5V ±50mV ripple

Samtec TMM-110-01-L-D-SM, mates with Samtec MM-110-02-S-D

Duty Cycle (TX=Transmit; RX=Receive)

10%TX 50% TX 100%TX 100%RX

33mA 54mA 80mA 28mA

TRANSCEIVER

Pin 11: 3.3 ±3%, ±100mV ripple

Westbay Technologies Ltd.

Sensitivity -97dBm typical @ 76.8kbps RF Data Rate
Range, Line of Site (based on

2dBi gain antenna)

1 mile

ENVIRONMENTAL

Temperature (Operating) -40°C to 80°C
Temperature (Storage) -50°C to +85°C
Humidity (non-condensing) 10% to 90%

PHYSICAL

Dimensions 1.65” x 1.9” x 0.20”
Weight Less than 0.75 ounce

西港机电科技(上海)有限公司

电话/Tel: [phone]
传真/Fax: [phone]
邮箱/E-mail: [e-mail]

上海市浦东新区海桐路 336 弄 1 号楼 701 室

Room 701, Building 1, Lane 336
Haitong Road, Shanghai, China 201204

3. Specifications

3.1 INTERFACE SIGNAL DEFINITIONS

The table below shows the connec tor pin numbers and associated functions. The I/O direction is
with respect to the transceiver. All outputs are 3.3VDC levels and inputs are 3.3V DC TTL. All
inputs are weakly pulled High and may be left floating during normal operation.

Table 1 – Pin Definitions

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Module

Pin

5,16 GND GND Signal Ground

10,11 PWR VCC Pin 10 (digital supply): 3.3 – 5.5V, ±50mV ripple, 50mA max

12 Input 9600_BAUD 9600_BAUD – When pulled logic Low and then applying power or resetting,

13 Output RSSI Received Signal Strength - An analog output giving an instantaneous

14 Input GI1 Generic Input pin

Type Signal

Function

Name

1 Output GO0 Generic Output pin

Output TXD Transmitted data out of the transceiver

2

3
4 Input GI0 Generic Input pin

6 Output GO1 Generic Output pin

7 Output CTS Clear to Send – Active Low when the transceiver is ready to accept data for

8 Input RTS Request to Send – When enabled in EE PROM, the OEM Host can take this

9 Output GO2 Generic Output pin

Input RXD Data input to the transceiver

transmission.

High when it is not ready to accept data from the transceiver. Keeping RTS
High for too long can cause data loss.

Pin 11 (Power Amplifier supply): 3.3V ±3%, ±100mV ripple, 100mA max

the transceiver’s serial interface is forced to a 9600, 8, N, 1 rate. To exit,
transceiver must be reset or power-cycled with 9600_Baud logic High.

indication of received signal strength. Only valid while in Receive Mode.

15 Input UP_RESET RESET – Controlled by the WJT844 for power-on reset if left unconnected.

17 Input Command/Data When logic Low, the transceiver interprets Host data as command data.

18 Input AD In 10 bit Analog Data Input

19 Output DA Out 10 bit Analog Data Output
20 Output GO3

After a Stable power-on reset, a logic High pulse will reset the transceiver.

When logic High, the transceiver interprets Host data as transmit data.