DB50 to DB25 DTE Screw-Lock Cable, 28 AWG

Overview

A db50 db25 dte cable is the serial lead between a legacy router or CSU/DSU with a DB50 port and the DB25, V.35 or DB15 equipment at the other end. The DB50 end is the SCSI-2-style half-pitch or full-pitch D-Sub shell that turns up on older Cisco hardware and serial concentrators; the far end is whatever the target device presents. Ours is twenty-five twisted pairs of 28 AWG stranded tinned copper under an overall foil plus braid shield with a drain wire, in a PVC jacket, wired straight-through, crossover or to your drawing.

Key Specifications

Connector A	DB50 male, metal hood with thumbscrews
Connector B	DB25 male or female, V.35 M/34 male, or DB15 male
Pin-out	DTE or DCE per inquiry; standard Cisco / serial pin-out on file
Conductor	28 AWG stranded tinned copper, 25 twisted pairs
Shielding	Overall foil + braid, drain wire
Jacket	PVC, black or beige, 8 mm to 10 mm OD
Length	1 m to 10 m standard; OEM on request
Build	Pin-out verified to your drawing

Which end combination do you need on this db50 db25 dte cable

The DB50 end is fixed; everything else is a choice. The three common builds break out the same DB50 port three different ways, and picking the wrong one is the usual reason a replacement cable does not work on the first try. Look at the port on the far device rather than at the old cable – the old cable may itself have been an adapter stack.

Variant	Far end	Where it is used	Note
DB50 to DB25	DB25 male or female	Legacy router and CSU/DSU serial ports	The default build; gender set by the far port
DB50 to V.35	V.35 M/34 male	Leased-line connections on older serial hardware	Same signals, different connector
DB50 to DB15	DB15 male	Serial concentrators and some terminal servers	Fewer signals carried
DB50 to DB50	DB50 male	Patch and extension between two DB50 ports	Straight-through unless you say otherwise

DTE or DCE: the question that decides the pinout

This is where most of these orders go wrong, and it is not a subtle distinction. A DTE device expects to transmit on the pin a DCE device expects to receive on, so a straight-through cable that joins two DTE ports crosses transmit and receive and nothing comes up. The fix is either a crossover build or a null-modem adapter, and knowing which you need starts with knowing what is at each end. Routers and terminals are DTE; modems, CSU/DSUs and most serial concentrator ports are DCE. If you connect DTE to DCE, build straight-through. DTE to DTE, build crossover.

End A	End B	Build you need	Common example
DTE	DCE	Straight-through	Router to CSU/DSU
DTE	DTE	Crossover	Router to router back-to-back, or router to terminal
DCE	DCE	Crossover	Two concentrator ports patched together
Either	Unknown	Send the equipment list	We will confirm before cutting cable

Where the DB50 shell comes from

DB50 is not one connector, it is a shell size that two different pitches borrowed. The half-pitch version is the one people mean when they say SCSI-2 style, and it is what you find on the serial and high-density ports of older networking hardware. The full-pitch version is mechanically larger and will not fit the same hood. Both are D-subminiature family connectors, and the tell is simple: hold a ruler across the contact row and compare it to the DB25 you already have. If you are unsure, photograph the port with something for scale and send it.

Shielding and pair count on a 25-pair run

Twenty-five twisted pairs is a lot of cable, and at 28 AWG the conductors are thin enough that a long run needs the shield doing real work. Foil gives high-frequency coverage, braid carries low-frequency interference and fault current, and the drain wire is what lets you terminate the foil properly instead of twisting it into a pigtail that stops working above a few hundred kilohertz. Both ends are metal-hooded shells with thumbscrews, so the screen is bonded to the hood at each end and the shield runs the whole length of the link. If the equipment at either end grounds the shell, tell us – that changes how we terminate the drain.

Typical applications for this db50 db25 dte cable

Legacy router and CSU/DSU serial console connections
Serial concentrator to modem or terminal
V.35 leased-line connections on older serial hardware
Custom serial patch cables for broadcast and industrial control
Keeping a legacy serial link alive during a migration

How to specify your build

Both connector types and genders – DB50 to DB25, V.35 or DB15.
DTE or DCE at each end, or the equipment make and model.
Pin-out – straight-through, crossover, or your drawing.
Length, and whether the run crosses power.
Hood style and jacket color.
Quantity, and whether this is a sample or a production order.

Workmanship and testing

Workmanship on DB50 builds follows IPC/WHMA-A-620 Class 3, the line is run under ISO 9001, and the termination range is 32 to 12 AWG. No DB50 assembly is boxed before 100% continuity and pinout are confirmed, and seal checking is quoted whenever an ingress rating is on the drawing.

Every production run can ship with RoHS and REACH declarations and the electrical report agreed at quotation; see certifications and material declarations. UL styles and other named approvals are built to drawing: we source to the style you specify and document it, rather than asserting a listing we do not hold. This assembly is built on the four lines covered under cable assembly and wire harness production, with nothing in the build handed to an undisclosed subcontractor. More background: cable assemblies for test and measurement. Tooling is quoted separately, cut in-house rather than brokered out, and owned by you.

Custom builds and ordering

Quote DB50 builds from 1 to 50 pcs and they ship in 3 working days; at volume the minimum is 500 pcs with 14 working days after approval. Tooling not already held adds around 10 working days. OEM and ODM DB50 runs go out under your part number and labeling and material certificates plus first-article reports are available.