Handheld Serial Data Analyser model SDA-02


A "multimeter" for troubleshooting serial data - this handheld serial data analyser displays, captures and analyses electrical asynchronous serial data. It uniquely accepts RS232, RS485/422 and CMOS/TTL level signals. It is ideal for field use and can be deployed in seconds. It has accurate time stamping facilities.  

As well as non-intrusively monitoring data, this analyser can also transmit user defined “test” messages and download captured data to a PC.


(Click picture for close up view)

  • Non-intrusively displays, captures and analyses electrical asynchronous data
  • Directly accepts RS232, RS485/422 and CMOS/TTL signal levels
  • Smaller to carry, quicker to deploy and longer battery life than PC based analysers
  • Byte by byte time stamping with 1mS or 100uS resolution
  • Transmit feature, up to 10 user defined test messages
  • Offline download of captured data to a PC, with optional time stamping details
  • Online download of continuous data, allowing use as a level converter and as either a full to half-duplex or half to full-duplex converter 
  • Modbus over Serial Line protocol capability (RTU & ASCII), automatically checks & generates CRC/LRC, can act as master or slave
  • Speed range (baud rate) from 50 to 115200 bps
  • Auto-configuration facility for speed, bits and parity
  • Full duplex two channel operation (e.g. RS232 transmit & receive)
  • Start and stop triggers, change speed on trigger, transmit on trigger
  • Designed and made by New Forest Electronics - requests for new features welcomed!
  • RoHS compliant (lead free) & CE marked
Unsolicited comments from users

"I would just like to congratulate you on a excellent product and it sounds like it has just got better"

"Everything works perfectly... It is a pleasure to use"

"The SDA has become an invaluable tool, to give an example I took the device to a company .. in Germany last year to do a Modbus communication test between our instrument and the plant's DCS. As usual there appeared to be no communication between the two. The instrument was blamed as Modbus was working in other areas. Using the SDA I demonstrated that the instrument was responding correctly, I was left to stand back while they panicked and the test was finished in a day not the allocated two. (The SDA paid for itself)"

Used worldwide by organisations large and small - click here to see analysis

What's included
  • SDA-02 handheld analyser
  • 119 page printed User Manual
  • Set of six general purpose test leads (details)
  • Pair of RS485 connection adapters (details)
  • 9 way D-type intercept adapter (not 25-way as shown above!) (details)
  • Two 9/25 way D-type converters
  • Batteries
  • 12 months warranty
  • Any firmware upgrades released in the next 12 months
  • Lifetime technical support by phone or email
Order code:  SDA-02 £455.00 + VAT (UK) Regret that this item is no longer available, production has ceased, as parts no longer available. However repairs or calibration of those already sold may be possible.  

 Optional USB adapters

USB adapter cables:-  enable a handheld analyser to download data to a PC not fitted with a standard R232 COM port (e.g. a notebook sized PC)
click here to view details

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 Optional accessory

Carrying case:-  A black soft PVC case, with three quarter zip and carry loop. It includes an internal pouch for test leads

Case: £25.00 + VAT (UK) Discontinued  

Firmware Upgrades

The handheld serial data analyser can be upgraded with new operational features after it has been sold. This is achieved by means of “firmware upgrades”, released by New Forest Electronics every few months. Click here for details (Use your browser back button to return here)

Application notes

The basics

One or more of the test leads or adapters supplied are plugged into the appropriate sockets on the front panel of the analyser. The leads are connected to the serial data of interest, and the analyser converts the electrical signals to viewable characters on its screen.

Monitoring data

To non-intrusively monitor data, a "passive" connection method is used. For instance, using the intercept adapter (see above), the SDA-02 is connected to the cable carrying the serial data of interest. This is done by unplugging the cable at a suitable point, and inserting the body of the adapter into the cable run. The adapter body maintains the continuity of the cable, and provides leads which plug into the sockets on the front of the SDA-02. By this means the analyser has access to the serial data, without affecting the flow of that data.

Transmitting data

To avoid contention (if RS232), and because usually only one item of equipment is being transmitted to, transmission is usually carried out in "Active" mode. In this case the analyser is directly connected to the equipment.

Further technical information

Downloading data to a PC (Application Note AN1) (1.2MB) >>

Using the Modbus facility (Application Note AN2)
(784KB) >> 


Ask the designer! For informed technical support,
further application information or
to request new features, email the designer of this product now!
(I aim to reply within the hour -
 during the UK working day only!)

Detailed specification

(a)  Data and General Features

Speeds: 50, 75, 110, 134.5, 150, 218.5, 300, 600, 1200, 1800, 2000, 2400, 3600, 4800, 7200, 9600, 14400, 19200, 28800, 31200, 33600, 38400, 57600, 115200 bps
(Channels 1 & 2 same speed or independent)
Time stamping: User selectable resolution of 1mS or 100μS
Data:  7 or 8 bits (excluding parity), with 1 or 2 stop bits
Parity: Error detection re Even, Odd, Mark or Space. None & Ignore settings
Display: Up to 168 characters, hex or ASCII/ISO 8859 with control codes. Normal and expanded modes, Modbus over Serial Line protocol modes, with CRC/LRC validation.
Memory: 16K character memory. Works on a continuous, rolling basis. (First in, first discarded).
User configurable as 1 x 16K file, or 2 x 8K, 4 x 4K independent files. (Only 1 x 4K available if time stamping enabled).
Triggers: To start and stop data capture, up to four bytes each. Auto re-start. Also “speed change on trigger” and “transmit on trigger” modes
Outputs: Download received data to PCs by serial playback of any captured data, “as received”, or in “hex format”, channels separate or combined, at any of above speeds, with or without time stamping information. Can show Modbus over Serial Line as extra information or frames
Transmit feature: Up to 10 user defined messages, each of up to 36 bytes, one of which may comprise up to 4 of the others, i.e. up to 144 bytes. Modbus over Serial Line framing option, with auto-generation of CRC/LRC
Size:  210 x 100 x 33/45 mm                        Weight:   340 gram / 12 oz

(b)  Electrical Parameters (Inputs)

   5 volt logic  
V28/RS232   RS485/422
Input Impedance:    HCMOS     133 Kohm typ.     12 Kohm min.
    Threshold level:     Hi: 2.4 V typ.  1.7 V typ.        +0.2 V max      
  3.2 V max.  2.4 V max.  


 1.4 V typ.   1.2 V typ. - 0.2 V min
  0.9 V min.  0.8 V max.  
Hysteresis: 1.0 V typ. 0.5 V typ.    70 mV typ.
Common-Mode Input         
Voltage range:   N/A  N/A  -7 V to + 12 V
Logic sense: Non - inverting inverting inverting

(c) Environmental

Environment:                 The analyser is intended for indoor use.
Temperature range:        0 to 40 degrees C (32 to 104 degrees F)
Humidity:                      20 to 80% relative humidity.

(d) Compliance 

Meets the requirements of the European Electromagnetic Compatibility Directive, 89/336/EEC as amended by 92/31/EEC and 93/68/EEC, by virtue of certification to:-

Emissions – BS EN55022:1998 Information technology equipment, Radio disturbance requirements – Limits and methods of measurement.
(Meets Class B (most severe), i.e. suitable even for a domestic environment).

Immunity – BS EN55024:1998 Information technology equipment, Immunity characteristics – Limits and methods of measurement.

Meets the requirements of the European Restriction of Hazardous Substances Directive, 2002/95/EC, (RoHS), and is therefore lead free

Made in UK by New Forest Electronics. CE marked.

Test leads supplied

A set of six general purpose 0.9 metre long test leads each with a 2 mm plug one end, for connecting the SDA-02 front panel sockets to CMOS/TTL data sources on PCB's:

  • 1 red lead with pointed probe (probe unplugs to provide a 2 x 2mm patch lead)

  • 1 red lead with hooked test probe

  • 1 blue lead with pointed probe

  • 1 blue lead with hooked test probe

  • 1 black lead with crocodile clip

  • 1 black lead with hooked test probe


  • pair of RS485 adapter leads with 2 mm plugs one end and connector blocks the other
  • To be adapted as required for connecting SDA-02 RS485/422 front panel sockets to 2 or 4 wire wire networks


  • An Intercept adapter for tapping into 9-way RS232 cables
  • Provides channel 1, channel 2 and 0v leads to connect into analyser input sockets
  • Suitable for 25-way cables by using 9-25 way converters supplied    



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                       © New Forest Electronics Tel. +44 (0) 1425 650089                 Issue 3.110    11 June 2024