“Shoot, move, and communicate,” the saying goes. They’re the three most important components of the infantry’s mission to close with and destroy the enemy. Good communications enable the rapid collection and dissemination of information within and between combat units so they can coordinate fire and movement successfully and in relative safety.
The US Army Signal Corps largely succeeded in providing infantrymen with reliable, portable communications systems in WWII. Where they failed, soldiers were able to fall back on simpler and less technologically dependent methods to accomplish their missions. A look at some of the different types of communication methods and equipment available to WWII infantry unit is below. They represent what would commonly be found in an infantry company. Mechanized units and higher echelons of command were provided with a wider array of communications equipment, but the average dogface would be familiar with the equipment and methods listed below.
The simplest form of communication was not limited to commanding troops in the immediate vicinity. Headquarters groups from the platoon level up to the regiment also used messengers, or runners, to relay information between two elements out of physical or visual contact with one another. These couriers could deliver written messages, although there were obvious security risks that rendered their memorization preferable. Runners were riflemen who were permanently assigned to headquarters groups as messengers, although any soldier could be employed as a as one when the situation required it. 
Hand and Arm Signals
Hand and arm signals were used when the tactical situation required silence or the noise of a firefight precluded hearing. A somewhat wide array of them appear in field manuals of the era, from the hand held up to signal the unit to halt to circling the right hand above the head to order the unit to assemble.
Flares are still used today. Different colors have different agreed upon meanings within a particular unit, although some are more or less universal. For instance, a red star cluster usually indicates an emergency or the need for a medevac. Raymond Gantter a platoon leader in the 1st Infantry Division described using a green star cluster for the signal to initiate a pincer attack into Geisbach, Germany. “The flare signal came at two-thirty and we pushed off.” Later, however, the use of flares led to some confusion. “I’d just given the order to fire the green flare that would inform the captain that all was well when a flare rose from the lower end of the village and burst in slow green brilliance across the sky…This wasn’t according to plan! The captain said he would answer my flare, but how could he be answering when we hadn’t yet signaled him? Another thing, this was a green flare, but it was a parachute flare, not a star cluster…[A]nother flare lighted the sky. Then another – a red parachute flare! Another…then another.” It turned out that the “Germans, taking alarm from the captain’s first flare, had surmised our pincer plan of attack and were doing their best to confuse us by themselves discharging a meaningless potpourri of flares.”
The EE-8 series field telephones were widely used during WWII and were deemed a secure and reliable form of communications. The handset and phone unit weighed nearly ten pounds and are connected by means of communication wire WD-1 or WD-130 . They were normally used at the platoon level and above. They had a range of 12-17 miles and could be configured in a variety of ways.
Field phones could either be connected to one another directly or routed through a switchboard. With a switchboard, a caller signaled the operator to connect them with another. Ideally, a switchboard operator – A Signal Corps soldier – was at the company level. His duty was to maintain contact between the battalion and its companies as well as the company and its platoons. The switchboard was rather bulky, so soldiers developed field expedient ways to establish networks. For example, while occupying a defensive position, Captain Charles MacDonald’s company spliced each of their platoons’ phones into a single wire, creating a party line, and had a separate line for battalion.
EE-8s did have drawbacks. It failed when wires were cut by enemy artillery, and often the range was shorter than advertised. Moreover, running lines was not always possible during highly mobile operations. It still proved to be a commo workhouse, and many of them survive and function today.
The SCR-536 was the Army’s smallest radio, and it was arguably the least reliable. It was designed as a lightweight, short-range, transmitter and receiver powered by batteries . Lieutenant Paul Fussell put it succinctly: “It took no more than two weeks to discover that the classy little Handie-Talkie radios we’d been equipped with wouldn’t work: in ideal conditions they might, but not in forests or mountains, or any of the places we were. We threw them away and regarded their use by others as evidence of their dangerous incompetence and naivete.” Nearly every memoir mentions their unreliability.
The SCR-300 was a portable backpack radio with a range of 3-5 miles and was used for the battalion net as well as by forward observers. It weighed roughly 35 pounds . Its ease of us and its reliability made it a well-liked piece of equipment despite its weight. It was used well into the 1950’s . It was a predecessor of more modern “man-pack” radios made from the 1960’s to the present day. While the company communications sergeant was responsible for the entire company’s commo equipment, most of the time basic riflemen served as radiomen .
 Soldier’s Handbook (Washington: War Department, 1941), 224-225.
 Field Manual 22-5: Infantry Drill and Regulations (Washington: War Department, 1941), pp. 187-96.
 Raymond Gantter, Roll Me Over: An Infantryman’s WWII (New York: Ivy Books, 1997), pp. 196-201.”EE-8 Military Field Telephone” on Olive-Drab
 Henri-Paul Enjames, Government Issue: US Army European Theater of Operations Collector’s Guide (Paris: Histoire & Collections, 2005), pp. 196-201.
 “EE-8 Military Field Telephone” on Olive Drab
 John D. Campbell and Harold P. Leinbaugh, The Men of Company K: The Autobiography of a World War II Rifle Company (New York: Bantam Books, 1985), p. 224.
 Charles B. MacDonald, Company Commander: The Classic Infantry Memoir of WWII (New York: Bantam Books, 1947), Kindle Editon, Loc. 499-520.
 Henri-Paul Enjames, Collector’s Guide, p. 205.
 Paul Fussell, Doing Battle: The Making of a Skeptic (Boston: Little, Brown, and Company, 1996), pp. 135-136.
 Enjames, Collector’s Guide, p. 206.
 “The SCR-300 Backpack Radio,” on Warfare History Network [https://warfarehistorynetwork.com/daily/wwii/the-scr-300-backpack-radio/]
 “Table of Organization and Equipment No. 7-17: Infantry Rifle Company” (Washington: War Department, February 1944), at Military Research Service [http://www.militaryresearch.org/7-17%2026Feb44.pdf].