As Enterprise is a prequel series, technology at the start of the pilot is consequently less advanced than seen in the other series.
First of all, Starfleet ships have no multiphasic shields yet. Outer protection of the ship's hull is provided by hull plating that can be polarized and absorb a certain amount of weapons fire. The plates do not provide protection against certain types of radiation.
Instead of phasers, the Enterprise fires 'phase cannons', which generally have the same effect as phasers, although not as powerful. Projectile weapons consist of conventional torpedoes. Photonic torpedoes are finally introduced by the end of season 2. Also, portable phase cannons for personal defence have just been issued, named 'phase pistols'. They replace traditional plasma rifles that were used until the 22nd century. They only have two settings: stun and kill. They can't evaporate objects and people.
The bridge layout is generally the same as in Star Trek, with the captain's chair in the center, helm in front, communications on the right, tactical at the left, and the science station behind the captain. Sub-Commander T'Pol, the Science Officer, has a telescopic viewer, like Spock did on TOS. Behind the bridge is a Situation Room, which consists of a large horizontal viewing station, where away missions are planned.
The Enterprise's engines are powered by a horizontal warp engine (like on the USS Enterprise, although it was named 'warp core' by that time), which is since recently capable of Warp 5 speed (contrary to the USS Enterprise from TOS, which could surpass Warp Factor 10). The warp factor is according to the old scale, meaning that the ship's speed is the cube of the warp factor times lightspeed (e.g. warp 3 means 3*3*3=27 times lightspeed). The scale was changed somewhere between the 23rd and 24th century, when warp 10 would be the absolute maximum speed (infinite velocity).
The Enterprise uses hatches to dock with other ships and enter and exit the ship. For away-mission in space, the ship has two shuttlepods. The shuttlebay opens from below, as opposed to from the back, and the shuttles are held in place by clamps. Each shuttle can hold a maximum of about five people. A small transporter is also available on Enterprise, invented some years before by engineer Dr. Emory Erickson, a personal friend of Captain Jonathan Archer. The transporter has been cleared for use on living material. However, the crew prefers to use shuttles and docking hatches, as transporting humans sometimes causes erratic side-effects, as seen in Enterprise: Strange New World (#1.4), Enterprise: Vanishing Point (#2.10) and Enterprise: Daedalus (#4.10) (basically, the crew is all but comprised of Dr. McCoys). By mid-season 3, knowledge of and experience with the transporters has increased enough to use the device on humans more often (only two people at a time, though). Interestingly, many species otherwise more advanced than humans (like the Andorians) don't possess transporter technology at this point.
The computer can scan for pathogens, but as there is no biofilter yet, the transporter cannot filter them out during transport. There is a special decontamination chamber to put crewmebers in quarantine when they have picked up something potentially dangerous.
Forcefields are only in an experimental stage (as seen in Enterprise: Vox Sola (#1.22)), so in case of a hull breach, the ship is protected from decompression by emergency bulkheads (much as in 20th century ships).
The tractor beam has not yet been invented by humans (Vulcans and Andorians have it, though). Instead, there is the 'Grappler', a harpoon-like device that can latch onto objects and pull them in. Not nearly as accurate as a beam, though.
There are no replicators for producing food. Basic ingredients are cultivated in the ship's hydroponics chamber, and there is something called a 'protein sequencer' that helps produce other ingredients. It can make the found taste somewhat artificial, according to some. The galley is where the ship's Chef creates meals for the crew, for which he is universally appreciated.
Communication within the ship goes mainly through intercoms attached to the wall, just as it was on the USS Enterprise in Star Trek. Portable flip-open communicators are available for away missions. The small version that can be pinned to a uniform isn't invented until the late 23rd or early 24th century.
Dates are indicated in months, days and years. Stardates are not yet used. Well, not by humans, anyway.
The universal translator is in its developmental stage. It contains many languages, but needs occasional adjustment and updates by Communications officer Ensign Hoshi Sato who was a knack for languages, to make conversations with alien species possible. She has a special work station on the bridge, much like Lt. Nyota Uhura had on TOS. Every crewman on an away mission should have a portable updated translator. Some languages prove to be so complex, context-sensitive, or contain so many dialects (like Klingon) that programming the device can be a full-time job. Hoshi ultimately refines the device so that it becomes more and more automated, so people without extensive knowledge of languages can also use it.
There is no general ship computer yet, although crewmembers can use a personal voice-activated computer for making log entries. It can only confirm commands through sounds, it does not return verbal answers.
Tricorders work quite the same way as their counterparts is the other series, albeit less powerful. Dr. Phlox has special medical tricorders, but also an imaging chamber (comparable to an MRI tunnel) for better internal scans. He also has to rely upon microscopes. Fortunately, Dr. Phlox is also very skilled in homeopathic and natural medicin as alternative cures.
Lieutenant Malcolm Reed starts devising a way to get the ship quickly into defensive mode in the episode Enterprise: Singularity (#2.9) during season 2. He plays with the idea of naming it "Reed alert", before settling on "Red Alert".
Starfleet members are aware of holographic technology, but it is in an early stage and not available for military or recreational purposes (such as a holodeck). Some species, such as the Xyrillians and the Romulans, have adequate knowledge for large-scale application. Instead of a holodeck, the Enterprise crew often organises movie nights where they watch mainly 20th century movies.
Starfleet Uniforms look like military overalls and are blue in color. Specific colored parts indicate to what section crewmembers belong. The spandex uniforms are not seen until the formation of the Federation.
Large space stations, such as Regula 1, are not yet in use. Small space-born research stations, like Yosemity Station (orbiting Earth) and Cold Station 12, do exist.
Following the Eugenic Wars, where genetic engineering and selective breeding were used to create a species of superhumans, genetic engineering in humans has been prohibited. During the next two centuries, the general attitude slowly changes, and in the 24th century, humanity has learned to safely and ethically apply some degree of genetic engineering to prevent congenital diseases.