"Science fiction writers, I am sorry to say, really do not know anything. We can't talk about science, because our knowledge of it is limited and unofficial, and usually our fiction is dreadful."
- Philip K. Dick

Simeon Kenton, of Kenton Space Enterprises, Unlimited, was in a terrible temper... His mildly whiskered saint's visage was screwed up into unutterable knots. In his tight-clutched fingers was a blue spacegram which he shook violently at his daughter at each choking pause in his peroration...

('Jurisdiction' by Nat Schachner)

Old Simeon glared at her and waved the offending spacegram so violently it ripped in his fingers.

Here's another use, from Off the Beam (1944) by George O. Smith:

A steward found Channing in the salon and handed him a ’gram. Channing smiled, and the steward returned the smile and added : “You’ll fix these ships to talk back one day. Wait until you read that one — you’ll burn from here to Terra !”

"Reading my mail?" asked Channing cheerfully. The average spacegram was about as secret as a postcard, so Channing didn't mind...