Air Transport: Not much civil aviation. but rapidly growing; the 1932 DC3 will revolutionize air travel. Military aviation branching into three fields: Bombers, Transports, and Fighters; scout planes also used. Airships (Zeppelins, mostly) provide commercial long distance air travel.
Cars: Stock cars tended to peak at about 50 MPH. Most were still open wheel, many open cockpit, but that was changing rapidly. Horseless carriages, however, where pretty much gone. The interstate system is still 25 years off, tho' it's being pushed for. The US Numbered Highways system is young. Most urban roads not yet cement nor asphalt; fit stone and brick typical. Unpaved roads quite common
http://en.wikipedia.org/wiki/U.S._Highway has list of the 1925 US numbered highways.
Direct dial not yet implemented in most areas, but rapidly being adopted. No long-distance networks for home phones in most areas, and where implemented, not universal access. Typical call involved picking up handset, cranking the handle to get the operator, requesting switch and line, and waiting for the switch operator(s) to connect you. Candlestick phones starting to fall from use. Households typically did not have phones; most calls were business to business, or payphone to business. Payphones existed in many neighborhoods; where direct dial not implemented, the operator had to listen for the coin tones. Phone booths becoming fairly standard in cities.
Special dedicated phone systems called Police Call boxes in use in many major cities. Often, they have a direct line to an operator, and a light for officers to know to call in.
Mechanical tabulators used in some industrial and government applications. A general purpose programmable computer designed but not implemented. In short, a missed opportunity due to lack of foresight. Dedicated mechanical computers being built into warships for fire solutions.
mostly hand-keyed, still, but moving to strip-output. Teletype also in use, uppercase and a few symbols, 5-bit ITA-1 Modified Baudot code used, often printing to strips. (A telegram often would be teletyped, then the strips glued onto the telegram pad.) ITA-2 code was just being released in 1930. All transmissions in uppercase. Radiotelegraphy and radioteletype both known and in military use. Early facsimile transmissions for news wire photographs. In 1930, 3 designs in competition.
Wire-recording known, but expensive. It's heyday was 1940-1945 (after which, tape replaced it). Direct to disk cutting of phonographs typical; phonographs mostly discs, not cylinders. Audio tape about to be invented in Germany. Optical encoding of sound on film developed; sound quality poor, but easily edited. Radio extremely common for entertainment; serials on phonograph disk pretty much the norm for national programs. Local production of radioplays from scripts also fairly common.
Video Recording: Almost exclusively on film, tho' television could have been recorded on wire. Television known, but not common, in the cities. Sets large, screens small (10+ cu ft for a 5" screen), monocrome, and usually live broadcasts. Films in theaters, often dual use with both stage and screen. Most had an organ or piano, as well, for accompanying the silent films, and many also had an amplified phonograph for playing the accompaniment discs.
Printing: Short runs (<500 copies) typically done using mimeographs (ink forced through a cut stencil onto paper) or the relatively new spirit duplicator, aka ditto machine (wax-ink on back of a master partially disolved by an alcohol solvent and physically deposited on the target page). Optical transcription for mimeographs known but rare, and possible but not documented for ditto.
Offset printing fairly standard for long runs, as is intaglio printing.
Dime novels common, in the now standard pocket format. Comics are often sci-fi or action oriented; some pretty brutal. Many news magazines.
Film & Photo: Talking pictures available, silent films still being made, but no longer drawing large crowds.
Color photography using several different methods possible; the two commonly available in 1930 were tripack film (3 layers of film, each sensitized to one color), and bipack (which was good for flesh colors, but not full spectrum). A third, the screen method, involved a filter with 72 colored (Red, Green, Blue) stripes to the inch, and rendered by a similar color overlay on the resulting B&W film. Also, 3-camera processes also used. If you see early color films, the three camera process was the standard in Hollywood well into the 50's.
Kodachrome is still 6 years off... so decent color cinema also 5 years off.
Color offset printing works best from the three-camera (or 3-strip) process.
Early color cinematography using three-strip negatives was being experimented with, but was not very successful.
Trains: Most trains are steam reciprocating engines, still. Some steam turbine engines developed, but not common use. Electric rail used in some systems, and some turbine-electric engines used. Diesel-Electric still 5 years off.
Boats: Some coal-fired boilers still in use; most commercial now using oil-fired boilers. Turbine-Electric possible, but not typically used. Metal hulls common; smaller boats often wood hulled. This is the heyday of liners for transport. (In 20 years, transatlantic air travel collapses the industry, resulting in cruise lines replacing travel lines.)
Field Radio: the first man-pack field radios are in development. Police radio-cars have receivers only; they still use the call-boxes &/or payphones to call the station. Most commercial boats rely upon field radios; most military battalion and higher HQ's have portable radio transceivers.
Word Processing: The manual typewriter with inked ribbon is the norm. Correction typically by erasure. Carbon paper common.
Most documents hand written.
Forms common; local forms often mimeographed. City and state forms often bound offset-printing; a carbon sheet needed for duplicates. Some forms use up to 8 sheets, requiring heavy pressure. Ball-end nibs can be used on carbon forms, but produce a blotchy top copy; pencils used frequently. Typically, carbon using forms typed, then the individual copies hand-signed.
Pens almost exclusively fountain pens. Various nib types, including a ball-end nib, commonly available.
Pencils include the standard wooden pencil (with or without eraser), carpenter's pencils, and the lead-holder (now typically considered a drafting tool). Some early screw-type mechanical pencils also used.
Photocopies: called photostats, they are literally a photograph of a document. Special notaries offered notarized photostats, doing the developing themselves to maintain chain of custody until bound and notarized.
Electricity: Typically AC, and only in urban areas. Gaslight replaced with electric lamps. Rural areas usually still using kerosene lanterns and candles. Electricity mostly used for lights, radios, and motor-appliances (especially washing wringers and agitators in washtubs).
The electric refrigerator is often commercially used, but only just becoming common in houses. Frozen foods rare. It's replacing the icebox (which placed a block of ice above an insulated chest).
Cooking: a variety of types of oven and range top exist.
Urban users tend to gas ovens burning natural gas and/or propane, and similar stove-tops. Electric stoves and ovens exist; they are just starting to make it into homes.
In rural areas, and poorer urban ones, wood and coal are used in iron stoves for cooking; some had oven compartments; if no oven compartment, a large lidded cookpot of cast iron, called a "Dutch Oven" was used. This author has personally seen a 1' deep, 2' wide, 3' long dutch oven used at camping events to bake turkeys...
Fine cookware is usually cast iron and/or copper. Tin and steel is also used.
Motorized electric mixers are available, as are blenders. Few foods are frozen; refrigeration is common, but not universal.
Buildings: the steel-frame stone-facade skyscraper is known. Elevators are available, but only common in tall (5+ stories) buildings. Handicapped accessibility is practically non-extant.
Medicine: Limited antibiotics, limited anesthesia, limited valid pharmacology. Surgery is common, and survivable. Germ theory well known. The flu still kills; polio is deadly.
What this all means for Magitech
To replicate with magic, locomotion will be essentially unchanged on the ground, save for how the power is generated. If cheap enough, magic heating for steam engines will be commonplace. If movement magics are cheap enough, the whole engine will cease to exist.
Airships will be more like naval vessels if magic exists which can lift them; otherwise, magic motors on zeppelins will result in indefinite range...
Cars will probably be much more evolved; horseless carriages will have been developed earlier, and aside from a lack of engine, the development is likely to be about 50-100 years ahead, simply due to lack of powerplant constraints.
Electricity can be replaced with stand-alone magic items, IF magic is cheap enough.
Radio and TV may or may not be replaced by magic items, depending upon how magic transmissions happen. Films, however, are likely to still exist unless image recording magics are common and tamper-proof.
If illusions are photographable, expect modern level SFX in B&W movies.
Written communication is likely to still be pretty much the same, save that automatic transcription is likely to be much better than real 1930's...
Medicine will likely be about the same point, or perhaps worse. With healing magics, many diseases will be treated by magic instead of medicine, and most physical ailments as well, at least for those who can afford it.