Designed & Made in the USA Since 1983
A 6-foot, 9-pin RS-232 null modem cable with female DB9 connectors on both ends (DB9F to DB9F). Crosses Transmit and Receive signal lines to allow two DTE devices — such as an RS-232 gage interface and a host PC or SPC data collection system — to communicate directly without a modem.
Connector Type – DB9 Female to DB9 Female
Length – 6 ft
Cable Type – Null Modem — Tx/Rx crossed
Compatible Interfaces – WedgeLink AT, WedgeLink SP, MobileCollect RS-232 Remote, GageWay Pro (Lever Converter for front channels)
Pin Count – 9-pin
$12.00
A null modem cable is a serial cable in which the Transmit (Tx) and Receive (Rx) signal lines — and typically the associated handshaking lines — are crossed between the two connectors. This wiring configuration allows two Data Terminal Equipment (DTE) devices to communicate directly without a modem or protocol converter.
Standard straight-through RS-232 cables route each pin to the same pin on the opposite end. When two DTE devices are connected that way, the Tx output of each device connects to the Tx input of the other — and no data flows. A null modem cable resolves this by routing each device’s output to the other device’s input. For a deeper explanation of DCE/DTE roles, straight-through vs. crossed wiring, and how RS-232 signal flow works, see our RS-232 Interface Guide.
In industrial metrology and SPC data collection setups, a null modem cable is needed when both connected devices present a DTE serial configuration — which is common when connecting an RS-232 gage interface directly to a host computer or data acquisition terminal:
If a gender changer alone doesn’t resolve a connection issue and a straight-through cable produces no output, a null modem cable is typically the correct next step. For non-standard or proprietary pinouts where a null modem still doesn’t work, see the ProAdapter.
Need a different DB9 connectivity solution? All four accessories are designed to work together with MicroRidge RS-232 gage interfaces:
Q: What is the difference between a null modem cable and a straight-through serial cable?
— A straight-through cable maps each pin to the same pin on both ends. A null modem cable crosses Tx and Rx (and related handshaking signals), allowing two DTE devices to communicate directly without a modem in between.
Q: Will this cable work with the WedgeLink SP?
— Yes. The DB9 Null Modem Cable is compatible with both WedgeLink AT and WedgeLink SP when the connection requires crossed Tx/Rx signal lines.
Q: Do I need a Level Converter Cable to use this with a GageWay Pro?
— It depends on which port you’re using. If you are connecting a single RS-232 device, you can use the RS-232 multifunction port on the back of the GageWay Pro directly — no Level Converter Cable required. If you need to use the front-panel gage channels with an RS-232 device, the Level Converter Cable (GW-LC) is required, and the DB9 Null Modem Cable then connects at the RS-232 output of that assembly.
Q: What if a null modem cable doesn’t solve my connection problem?
— If the connected device uses a non-standard or proprietary pinout, the ProAdapter is the appropriate next step. It allows you to assign any signal to any pin without soldering.
DB9-NFF-6 Specs | |
|---|---|
Connector Type | DB9 Female to DB9 Female |
Length | 6 feet |
Cable Type | Null Modem — Tx/Rx crossed |
Compatible Interfaces | WedgeLink AT, WedgeLink SP, MobileCollect RS-232 Remote, GageWay Pro (Lever Converter for front channels) |
Pin Count | 9-pin |