DLM400 Serial RS-232 RS-422 RS485 Monitor/Tester/Simulator/ Emulator

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  DLM400 series Release Notes in MS Word Format   (
including latest improvements)

Buffer Capacity

304,000 TD/RD records

Data Rates 75-115,200 (230,400 bps half duplex) Asynchronous, 75-64 kbps Synchroneous, External Clock

Electrical Interfaces

RS422, RS232, RS423, RS485 Menu selectable.
Voltage Menu Selectable 5 volts or 8 volts Plus TTL


Asynchronous, Synchroneous,  Bisynchronous, SDLC/HDLC

In the Box

The DLM400 package includes all you need to begin monitoring and testing:
A 2 compartment carrying case, wall transformer, batteries, 102 LED Break out Box, the BOB100, 9 pin to 25 pin adapters, 3 foot monitoring cable , manual plus quick start instructions.


Within 20 characters received, determines protocol, bit rates, number of bits per character, sync character, parity and then automatically sets the proper parameters and presents captured data to the screen

Bit/Block Transmission Tests and patterns

Output any of the following patterns:
RD or TD buffer; FOX;All characters from 0x00-0XFF; Predefined user strings; FOX2; 0x00; 0xFF; 511 Pattern; Entire ASCII set.

Historical Data

Saves/displays state of the modem control lines with each byte posted to the capture buffer


Triggers can be set to start or stop data capture on user-defined strings of up to 80 bytes or on interface signal pattern. Start triggers can be automatically reset after occurrence of stop trigger by DLM400 to provide "snapshots" of subsets of the data stream.

Physical- Handheld

9.25 x 5.50 x 1.37 inches; 23 ounces 23.5 x 13.5 x 3.3 centimeters; 630 grams.
Full 64 key QWERTY keyboard PLUS PC style directional keypad


8 line by 30/40 character  Liquid Crystal Display

Response Analysis

Average times between triggers to the millisecond (up to four hours) to measure human, computer and communications line performance on all RS232, RS422, RS485 Circuits.


Analysis BERT performance statistics and performance calculations on Async RS232 and RS422 Circuits


Online printable help for all functions


Odd, Even, None



Power Source

9-volt battery ( 9 hours with alkaline) or by supplied external transformer

Questions. Or call us at 650-323-0148.

Protocol Analyser Homepage of hand held RS232 / RS422 MONITORS & Test Equipment