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Model 600, Cat#301020 RS232 Breakout Box / Interface Analyzer Tests EIA RS232, CCITT V.24 and MIL-188C

    EIA RS232 Interface AnalyzerEIA RS232 Interface AnalyzerEIA-CCITT MODEM TERMINAL INTERFACERED INDICATOR DISPLAYEIA RS232 Interface Analyzer
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    • EIA RS232 Interface Analyzer
    • EIA RS232 Interface Analyzer
    • EIA RS232 Interface Analyzer
Base Price:
Catalog No: 301020
Model No: 600
Description:Compatible with EIA RS-232, CCITT, V.24 & MIL-188C
Display:All modem & terminal interface signals
Product Type:Breakout Boxes/Interface Analyzer
Interface:RS-232 Interface
Application:Testing of computer's serial data interface
Feature:Simultaneous display polarity, activity, validity of key interface signals.
Ruggedized:Virtually indestructable

  • Simultaneous display polarity, activity, validity of key interface signals.

  • Cable Interface Diagnostic tools.

  • Cable Interface Testing.


Shipping Terms

Shipments are made via UPS Ground, unless otherwise specified. Freight charges are prepaid and added to your invoice. We can estimate the freight costs for you.

We can ship freight collect on your account, just provide your UPS Account Number.

We can also ship via the carrier of your choice. Provide the details and your account number.

Products shall be shipped F.O.B. Electro Standards' facility. Title to and risk of loss or damage to the products shall pass to you upon Electro Standards delivery of the products to a carrier for shipment. Title to software will remain with the applicable licensor. Electro Standards' prices do not include shipping and handling charges. Electro Standards reserves the right to use its own discretion in the manner and routing of shipments. Electro Standards shall be permitted to deliver products in separate lots.

Shipping Return Policy

  • To return an item, contact Electro Standards at 401-943-1164 to obtain a Return Material Authorization (RMA) number. RMA numbers are valid for 30 days after the date of the shipment and cannot be extended or re-issued. We are unable to accept returns without an RMA number.
  • All returns except those of defective product are subject to a 15% restocking fee, and additional charges for handling or freight are refunded only in cases of defective products.
  • Return freight must be shipped prepaid. We recommend that you insure the package as you are responsible for risk of loss on all returned packages. We recommend that all cartons are properly packed as Electro Standards is not responsible for product damaged en route. We do not issue call tags for product returns.
  • Returned product must be clean, undamaged, and complete with all manuals, accessories, documents and packaging. The items must be in a resalable condition.
  • The product must have with it a copy of the original invoice or packing slip and the appropriate RMA paperwork.
  • If your item is not working properly, please contact Electro Standards at 401-943-1164 for help in trouble-shooting your application.
  • If the product is defective, Electro Standards will repair or replace that item (at our discretion) upon receipt and evaluation of the original product.
  • Electro Standards reserves the right to authorize product returns after 30 days from the invoice date in some cases. If the product is accepted after 30 days, credit will be issued toward future pruchases only and some additional restocking charges may be applied.
  • All credits from RMAs must be used within one calendar year of issue.

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Model 600 "Blue Box" Breakout Box EIA RS-232 Interface Analyzer for Testing Serial Data Interfaces such as EIA, RS232, CCITT V.24 and MIL-188C

  • Red LED's simultaneously display polarity, activity, and validity of key interface Signals!

  • Cable Interface Diagnostic tools.

  • Cable Interface Testing.

  • ESL Breakout Boxes are Made in the USA. *Lifetime Warranty


  • Easy testing of computer's serial data interface.
  • Compatible with EIA RS232, CCITT V.24, and MIL-188C.
  • Easy determination of proper data cable design.
  • Lightweight, pocket-sized and battery powered.
  • Virtually indestructible aluminum case with metal hinge and latch.
  • The breakout box of choice for computer room field service.
  • Lifetime Warranty against manufacturing defects!
  • Easily inserted in series between DTE (Data Terminal Equipment) and DCE (Data Comm Equipment).
  • 50 Test points to access all 25 pins of both DCE and DTE connector.
  • Test synchronous or asynchronous modems, terminals, and multiplexers.
  • 24-mini-switches provide capability to program each signal for make or break.
  • Displays all modem & terminal interface signals.
  • Separate EIA cable facilitates use at either modem or terminal end.
  • Full-duplex and half-duplex monitoring.
  • On GSA Schedule!


The Model 600 EIA RS-232 Interface Analyzer is used at the standard EIA RS-232 or CCITT V.24 data interface of modems, multiplexers, terminals, and computers. Model 600 provides access to and monitoring of all data, timing, and control signals.

The Model 600 utilizes light emitting diodes (LEDs) to display polarity, activity, and validity of all interface signals. The battery-powered LEDs are buffered to prevent loading of the data interface. Miniature rocker switches allow the user to program 'make' or 'break' for each signal at the DCE/DTE interface. Continuous positive and negative voltages are conveniently available on the test points and can simulate handshaking or data signals. An ample supply of mini-patchcords provide for cross-patching or loopback patching of signals at the front panel test point array.

A complete table of EIA/CCITT standard interface signal description is provided inside the unit for ready reference during testing. A covered compartment provides secure storage for mini-patchcords and an EIA ribbon cable.


The Model 600's high-efficiency LEDs clearly indicate the status of key signals at the EIA/CCITT data interface. For regularly monitored signals, a SPACE condition is signified by a red indication. A MARK condition is signified by an OFF indication. An improper signal level (between 3 volts and -3 volts) or an open circuit is also displayed as an OFF indication.  Active clock signals result in an alternating on and off indication that is directly related to the clock duty cycle.

For signals monitored via the TEST pin, a pair of LEDs is used to indicate valid EIA/CCITT voltage levels. A SPACE condition is signified by a red indication from the POS LED. A MARK condition is signified by a red indication for the NEG LED. An improper signal level (between 3 volts and -3 volts) or an open circuit is indicated by a simultaneous OFF condition from both the POS and the NEG LEDs.


  • Input Signal: /- 25 volts per EIA RS-232
    • More positive than 2.5 volt for ON indication.
  • LED Circuit Input Impedance: Exceeds 30K ohms.
  • Operating Temperature: 0°C to 50°C.
  • Storage Temperature: -20°C to 90°C
  • Humidity: 10% to 90% without condensation.
  • Size: 4.0 x 5.25 x 1.75 inches (10.16 x 13.33 x 4.45 cm)
  • Weight: 15 ounces (426 grams)
  • Power: Four 1.5V, size AA batteries
  • Display: 15 high-efficiency red indicators
  • Test Points: 50 test points provide access to all 25 pins on both the DCE and DTE connector, 1 to access test LEDs and 2 to provide continuous positive and negative test voltages.
  • Switches: 24 mini-rocker switches for ON/OFF control of signals passing through between DCE and DTE connectors.
  • I/O Connectors: To DCE, a 25-pin EIA socket. To DTE, a 25-pin EIA plug.
  • Cables and Patchcords: One 10" M/F EIA ribbon cable for connection to DCE or DTE. Three single (1-to-1) patchcords and one triple (3-to-1) patchcord for use with test points.
  • EIA/CCITT Modem-Terminal Interface Label: Attached to upper panel. Describes relationship between EIA, CCITT, Signal Nomenclature, and Signal Source.
  • Packaging: Aluminum case, metal hinge and clasp. Storage compartment for cable and mini-patchcords.

Model 600 is available to government purchasers on our GSA Schedule GS-35F-0286V. Call for discounted price and terms.

A manual accompanies each unit and provides application assistance. Need more help? Contact Electro Standards, provide the serial number of your Model 600, state your application and question, and you will receive a helpful answer.

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