However, the phrase is likely meant to be more friendly and casual, with "viejo" being used in a playful way rather than literally. It's similar to how we might say "Give me a shout on Monday, buddy" in English.
Here are some possible interpretations:
* "Call me on Monday, pal." This emphasizes a friendly tone and a request for a call.
* "Don't forget to call me on Monday, okay?" This implies a reminder, perhaps for something important.
* "Let's talk on Monday, alright?" This suggests a conversation or meeting scheduled for Monday.
The exact meaning depends on the context and relationship between the speaker and the listener. It's important to remember that language is often nuanced and can carry different meanings depending on cultural context.