2600.network Dialup Service

Original Article ↗ Hacker News Discussion ↗

Dial‑up over modern networks (VoIP, IMS, cellular)

  • Several comments explore running analog modems over VoIP or VoLTE/IMS.
  • Consensus:
    • Works best with G.711 (µ‑law PCM) because it’s essentially uncompressed 8 kHz audio, like legacy PSTN.
    • Predictive/lossy speech codecs (G.722, AMR, GSM full/half‑rate, EVS) degrade modem signals; lower baud rates (2,400–9,600 bps) may still function.
    • Jitter and packet loss are usually bigger problems than bandwidth; short, low‑speed exchanges (e.g., card terminals, short faxes) succeed more often than long 56k sessions.
  • Fax over VoIP is often stabilized via T.38, which bypasses audio; an analogous solution for general modems is mentioned (V.150.1), but is rarely deployed.
  • GSM Circuit‑Switched Data (CSD) once allowed digital‑to‑modem bridging in the network, but is now mostly unavailable; some experimentation continues where 2G still exists.

Using 2600.network and BBSes today

  • To connect without POTS, people suggest:
    • Using an ATA (analog telephone adapter) with G.711 and a real modem (expect 2,400–14,400 bps).
    • D‑Modem (software SIP modem) as a VoIP‑native option.
  • ATAs solve the line problem but not the need for an actual modem.
  • For those unfamiliar with BBS: it’s a text‑mode, single‑ or multi‑user system over a terminal‑like connection, often similar to telnet BBSes today.

History and meaning of “2600”

  • 2600 Hz was a control tone in older long‑distance networks, signaling an idle trunk.
  • Phone phreaks used 2600 Hz and multi‑frequency (MF) tones (“blue boxes”) to seize trunks and route unauthorized calls, exploiting in‑band signaling.
  • The 2600 Hacker Quarterly zine, some Cisco routers, and various hacker groups and meetups take their name from this tone.
  • The phreaking era, payphones, red/blue boxing, and early hacker culture are reminisced as formative and largely gone.

Dial‑up in appliances and out‑of‑band access

  • Past enterprise gear (e.g., search appliances, IBM tools, telecom equipment) often embedded modems for out‑of‑band diagnostics, avoiding firewalls but raising theoretical trust concerns.
  • Similar patterns still exist (e.g., appliances with reverse‑shell “diagnostic modes,” or dial‑up‑like email relay systems).

Related niches and nostalgia

  • References to 2600, Phrack, YIPL/TAP, C*Net, and war‑dialing/war‑driving communities.
  • Debate over whether POTS still exists vs. landlines now being mostly VoIP‑backed.