If it did not apply to low voltage this exception would not exist:
(b) Low Voltage. By special permission, smaller working
spaces shall be permitted where all exposed live parts
operate at not greater than 30 volts rms, 42 volts peak, or
60 volts dc.
The telephone equipment would be covered by a Chapter 8 article. The rules in Chapters 1-7 do not apply to Chapter 8 articles.
90.3 ...Chapter 8 covers communications systems and is not subject to the requirements of Chapters 1 through 7 except where the requirements are specifically referenced in Chapter 8.
Thanks Don, it appears telecom work spaces is deferred to "ansi tia-570-b work spaces" . But I am still having a hard time coming up with definitive numbers and distances.
OSHA 1910.303(g)(1).... references working space requirements for electrical equpipement 600v or less. It seems this would apply to all jurisdictions since it comes straight from OSHA. Also sounds like OSHA adopted/ mimiced some of what is referenced in NFPA 70.