Passmark Serial & Parallel Loopback Plug

The loopback plugs enable the testing of parallels.


In Stock, Delivery time: 1 - 3 days

Further information
Plug type

BurninTest Software V10
Version: Windows | Licensing: Single user
BurninTest Software V10
Version: Windows | Licensing: Single user
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Product number: PM013
Manufacturer: Passmark


The loopback connectors allow testing of serial and parallel ports.


  • High quality, fully molded loopback connectors for serial and parallel ports
  • The quickest and most effective way to verify that your serial (RS232) and parallel ports are working properly. work
  • These adapters plug into the serial and parallel ports of a computer and allow the data and signal path to be looped through by connecting the transmit and receive pins together.
  • For use with BurnInTest Professional

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The serial loopback connector is a 9-pin female connector (DE-9)

In addition to testing the receive and transmit functions, the following RS232 signal pins are also tested:

  • Release to Send (CTS)
  • Request to send (RTS)
  • Data set ready (DSR)
  • Data Terminal Ready (DTR)

The parallel loopback connector is a 25-pin (DB-25) connector.

The parallel port is also known as the printer port.



Windows 98, ME, 2000, 2003, XP (32-bit and 64-bit), Vista (32-bit and 64-bit), 2008 Server (32-bit and 64-bit), Windows 7 (32 -bit and 64-bit), Windows 8 (32-bit and 64-bit), Windows 10 (64-bit) and Linux platforms are supported provided you have the correct version of BurnInTest.

To use the plugs on Windows, BurnInTest Professional v2.0 or higher is required. For Linux, BurnInTest is required for Linux v1.0 or higher.

Since there are several ways to create loopback plugs, we cannot guarantee the compatibility of our plugs with any software other than BurnInTest Professional.

Technical Data

Loopback serial connector

The serial port on IBM compatible PCs conforms to the RS232 electrical standard and uses a male DB-9 connector. (Older PCs can use a DB-25). The DB-9 connector like the following 9 pins.

If you don’t want to make your own connectors, you can always purchase our serial and parallel loopback connectors.


DB-9 pinEIA abbreviationDescription
1DCDData carrier detect
2RXDReceive data
3TXDTransmit data
4DTRData terminal ready
5GNDSignal ground
6DSRData set ready
7RTSRequest to send
8CTSClear to send
9RIRing Indicator


To make the loopback connector, the following pins must be connected together

Receive and send (2 & 3)
Request to send and clear to send (7 & 8)
Detect data medium, data set ready and data terminal ;t ready (1, 6 & 4)
This diagram shows the pinout connections that need to be made. It is the rear view of the DB-9 female connector that is required for the plug. The red lines and gray dots show the connections that need to be made.

Paralleler Loopback-Stecker

Die parallele Schnittstelle von IBM-kompatiblen PCs war schon immer mit einem DB-25-Stecker ausgestattet. Im Laufe der Zeit hat sich die elektrische Schnittstelle jedoch mit der Einführung von verbesserten und bidirektionalen parallelen Anschlüssen verändert. Wir glauben, dass dieser Stecker mit allen Arten von parallelen Anschlüssen funktioniert.



DB-25 PinDirectionDescription
2OutData bit 0 (Least significant bit)
3OutData bit 1
4OutData bit 2
5OutData bit 3
6OutData bit 4
10InAcknowledge status
11InBusy status
12InPaper out status
13InSelect status
15InError status

Um den Loopback-Stecker herzustellen, müssen die folgenden Pins miteinander verbunden werden

  • Daten 0 und Fehlerstatus (Pin 2 & 15)
  • Daten 1 und Auswahlstatus (3 und 13)
  • Daten 2 und Papierausgangsstatus (4 & 12)
  • Daten 3 und Quittungsstatus (5 & 10)
  • Daten 4 und Besetzt-Status (6 und 11)

Dieses Diagramm zeigt die Anschlüsse, die vorgenommen werden müssen. Es handelt sich um die Rückansicht des DB-25-Steckers, der für den Stecker benötigt wird. Die roten Linien und grauen Punkte zeigen die Anschlüsse, die hergestellt werden müssen.