The status monitor is a text that smsd writes every second to stdout. This is normally your console but you can redirect it to any device or file.
The status monitor shows you what your modems are actually doing. Each character represents one modem. The first one is the first modem in your config file.
The status may be:
s = sending
r = receiving (or checking received SM)
i = idle
b = blocked (after multiple errors)
- = not configured
Example:
iiiriisssisss---
iiiriisssisss---
rriiiiissisis---
rriiiiiiiiiii---
iiiiiiiiiiiir---
Run smsd with the option -s if you want the status monitor.