There are mainly 4 tones in Mandarin Chinese, first tone (marked "1"),second tone ("2"), third tone ("3"), and fourth tone ("4").
Unlike Mandarin Chinese, Suzhou dialect, derived from Middle Chinese, has 7 tones theoretically.
In traditional Chinese phonology, syllables that ended in a stop in
Middle Chinese (i.e. /p/, /t/ or /k/) were considered to belong to a
special category known as the entering tone. These final stops have
disappeared in most Mandarin dialects, with the syllables
distributed over the other four modern tones in different ways in
the Suzhou dialect.
In Suzhou dialect, the final plosives are not deleted completely as they are in Mandarin Chinese, they gradually reduce to glottal stops /ʔ/.
However, in the actual daily pronunciation not all the 8 tones are pronounced which depend on the voicing of the consonants.
Here is a chart for the tone system in Suzhou dialect.
(retrieved from Wikipedia)
Topics for further practice:
It seems that the phenomenon of "tone sandhi" appears in Suzhou dialect where one word possesses two or more different tones and its tone varies according to the word combination.