The telephone was invented in 1876 and wouldn't be widely available until at least the 1910s, but people had been "calling" each other since the Middle Ages. How was that possible? Well, the word "call" has shifted in meaning throughout the centuries, and during the Regency Era, it came to mean a physical visit.
In Jane Austen's Pride and Prejudice, Mrs. Bennet begs her husband to "call on" Mr. Bingley and welcome him to the neighborhood. Though Mrs. Bennet was actually scheming to introduce Mr. Bingley to her five daughters, the social structure of the day insisted upon regular visits, or "morning calls." When calling on someone, you were basically networking, and it was important to your social standing to maintain visits with friends, relatives, and acquaintances.
The Meaning
The word "call" came from the Proto-Germanic root "gal," meaning to shout or cry out. The Old Norse word "kalla" simply changed the hard 'g' sound to the 'k' sound. By the mid-1200s, the word had evolved to "callen" and was used to mean crying out to someone in particular, like calling for someone's attention.
During the mid-1700s, France began to popularize using a card when visiting someone. The card stated your name and allowed the visitee to decide whether they wanted to receive guests or not without having to reject you in person. These cards were deemed "calling cards" because they were used to gain the visitee's attention. England followed the trend soon after, and "making a call" to someone then meant to visit them, with or without a calling card.
The Rules
As with many other parts of Regency Era society, there were strict rules on how and when to call on someone. A person of a lower class ought to wait until those of a higher class sent a calling card first, but visiting people within your own class was acceptable. And if you were new to the town, you waited for your neighbors to come to you.
You also had to abide by the time limits for these social calls, lest you be thought of as someone who has overstayed their welcome. Making a call only took about 15 minutes, and it should never go longer than 30 minutes. The whole point of calling on people was to maintain connections with short chats, and then leave before taking up too much of the host's day.
The Schedule
These visits may have been named "morning calls," but they actually took place in the afternoon. The time considered best to call on was between 1:00 and 4:00 pm. But it was also important to know the general schedule of the person you were visiting. You wouldn't want to rudely interrupt them while they were in the middle of their midday meal.
Knowing when to "take your leave" was just as important. If you did visit at a bad time but they were too polite to reject you, it was up to you to leave as quickly as possible. Also, if other visitors called while you were there, you would wait for them to come in, make your goodbyes, and then leave the home so as not to overwhelm the host of all the callers. Topics of conversation needed to be light enough that you could abruptly end the chat and leave as soon as you sensed you had become an inconvenience.
Calling on someone was the way you stayed in touch with your neighbors, but also with the goings-on in the world. These visits were vital to both the visitors and those being visited. Calls, then, remain an important communication tool, whether they are in-person meetings or chats on our phones.