LFH60 DB37 Screw-Lock Cable, RS-449 Serial

Overview

An lfh60 db37 cable is the serial breakout lead that gets an old concentrator card back on the network. The LFH60 – Low Force Helix – is the 60-pin half-pitch D-Sub shell used on Cisco, Sun and other serial concentrator WIC and HWIC cards; the DB37 side is the standard RS-449 connector, and the V.35 variant breaks the same signals out to the M/34 V.35 connector. Ours is thirty twisted pairs of 28 AWG stranded tinned copper under an overall foil plus braid shield with drain wire, in a PVC jacket, with metal hoods and jackscrews at the LFH60 end and thumbscrews at the far end.

Key Specifications

Connector A	LFH60 male, metal hood with jackscrews
Connector B	DB37 male or female (RS-449) or M/34 male (V.35)
Pin-out	DCE per RS-449 / V.35 standard; DTE on request
Conductor	28 AWG stranded tinned copper, 30 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

DCE or DTE on this lfh60 db37 cable

The default build is DCE, because that is what a concentrator card port expects to see on the other end of a leased-line connection. If you are patching two DCE ports together, or building a test fixture where the cable has to behave like a modem, ask for the DTE version and we will cross the appropriate pairs. Getting this wrong does not damage anything – the link simply never comes up, which is confusing because the cable looks perfect and tests continuous. Tell us what is at each end and we will confirm the wiring before cutting anything.

Build	Use it when	Notes
DCE (default)	Concentrator card to a DTE device or a leased-line presentation	The standard RS-449 / V.35 breakout
DTE	Two DCE ports patched together, or a modem-simulating test fixture	Transmit and receive pairs crossed
Custom	Your own diagram, or an undocumented legacy panel	We verify pinout against your drawing 100%

RS-449 or V.35: two breakouts, one shell

Both are serial interface standards from the same era, and both turn up on the same hardware. RS-449 defines the electrical and mechanical characteristics and uses a DB37 connector; V.35 defines the electrical interface for a 34-position connector and is the one you find on leased-line and data-circuit equipment. The signals overlap, which is why one LFH60 port can be broken out either way. What decides it is purely what is at the far end – look at the port, not at the old cable, because the old cable may have been part of an adapter stack that hid an intermediate connector.

Far end	Connector	Where it is used	Confirm before ordering
RS-449	DB37 male or female	Legacy leased-line and data circuit equipment	Gender of the port on the device
V.35	M/34 male	Older serial concentrator cards and modems	That the port is V.35 and not a look-alike
Both	DB37 and M/34	Test benches that see everything	Pin-out per port

Thirty pairs: why the assembly is bigger than it looks

Sixty positions at half pitch means thirty pairs, and thirty pairs of 28 AWG is a substantial bundle – which is why the jacket is 8 mm to 10 mm OD and why the hood at the LFH60 end is not optional. The jackscrews matter too: they are what holds the connector into the card against the weight of that bundle, and a cable without them will slowly lever itself out of a vertical card. If the run is longer than a few meters, tell us – at 28 AWG the resistance per conductor becomes part of the link budget, and on a long run we may suggest a larger conductor or a shorter cable.

What to send us with the order

These are legacy links, documentation is often missing, and the fastest route is usually a photograph. Three things settle almost every order: the card or port at the LFH60 end, the connector at the far end, and whether the link ever worked with a cable you can send us.

What to send	Why it matters	If you do not have it
Card or port model at the LFH60 end	Confirms the pin-out family	Photograph the port with something for scale
Far-end connector and gender	Decides DB37 or M/34, male or female	Photograph the device port
DCE or DTE	Decides whether pairs are crossed	Tell us what is at each end and we will work it out
Length	28 AWG is thin; long runs need thought	Measure along the route, not the straight line

Typical applications for this lfh60 db37 cable

Cisco, Sun and other serial concentrator WIC / HWIC cards to RS-449
V.35 leased-line connections on serial concentrator cards
DCE patch cables for serial test fixtures
Custom serial patch cables for broadcast and industrial control
Keeping a legacy serial installation running through a migration

How to specify your build

Far end – DB37 RS-449 or M/34 V.35, and the gender.
DCE or DTE, or the equipment at each end.
Pin-out – standard, or your diagram.
Length, measured along the route.
Hood style and jacket color.
Quantity, and whether this is a sample or a production order.

Workmanship and testing

LFH60 builds are made to IPC/WHMA-A-620 Class 3 workmanship inside an ISO 9001 system, over a 32 to 12 AWG range. No LFH60 assembly is boxed before continuity and pinout are confirmed, and seal checking is quoted whenever an ingress rating is on the drawing.

RoHS and REACH declarations are provided per project together with the agreed test reports; the documentation scope is listed under certifications and compliance. If your drawing specifies a UL style, we build to that drawing and supply the UL reference with the shipment instead of substituting an equivalent. Injection parameters for this part are developed against the jacket material using the approach documented under overmolding and injection molding. More background: cable assemblies for test and measurement. Any tooling we cut for this part stays yours, maintained in our own tool room under your part reference.

Custom builds and ordering

For LFH60 builds, prototypes run from 1 to 50 pcs with a 3 working day turnaround; volume orders begin at 500 pcs and ship 14 working days after approval. Tooling not already held adds around 10 working days. LFH60 builds go out under your part number and labeling, and material certificates and first-article reports are available on request.