Dialup Network In A Box

This is a self-contained, portable telephony network which allows us to connect and analog modems and ISDN adapters at retrocomputing events.

The setup (as of Q4/2019) consists of:
  • Auerswald COMmander Basic2 PBX with 8x S0 (ISDN BRI) ports, 16x a/b (analog) ports, 8x Up0 (ISDN) ports and 1x S2M (E1 ISDN PRI)
  • 1U Rack-Mount Atom PC with 4-port E1 (DAHDI) card and FreeSwitch: Emulates public telephone exchange
  • Livingston Portmaster 3 RAS with ability to terminate 30 ISDN or analog modem calls

Telephony Setup

The physical setup looks like this:

Logical Setup:

This shows the logical setup including PCs and associated software:


Ethernet Switch configuration

We have an old 16-port gigabit ethernet switch (DELL PowerConnect 2716) in our setup.

VLAN 1 (admin)

  • Port 1: untagged
  • Port 7: PC eth1 (tagged)
  • Port 8: admin laptop (tagged)

VLAN 11 (admin)

This is a "jumper" from VLAN 1 (untagged) to VLAN 11 (tagged) as the switch doesn't natively support its web interface on a tagged IP

  • Port 4: untagged
  • Port 7: PC eth1 (tagged)
  • Port 8: admin laptop (tagged)

VLAN 3999 (uplink)

  • Ports 9..16
  • Port 8: admin laptop (tagged)

VLAN 4000 (auerswald)

  • Port 2: Auerswald (untagged)
  • Port 7: PC eth1 (tagged)
  • Port 8: admin laptop (tagged)

VLAN 4001 (PM3)

  • Port 3: PM3 (untagged)
  • Port 7: PC eth1 (tagged)
  • Port 8: admin laptop (tagged)

E1 configuration

E1 ports on the atom1u machine with DAHDI + freeswitch

The ports are allocated as follows:

  • Port E1/1: Auerswald
  • Port E1/2: PM3
  • Port E1/3: Unused
  • Port E1/4: icE1usb

The ports, as well as those of the portsmaster + auerswald are brougiht out on the keystone patch panel. They must be connected as stated above using E1 cross-over cables. those have a special pin-out, and are not to be confused with Ethernet cables (straight or cross-over).

IP Network configuration

VLAN 1/11 (admin)

IP Host dell2716 switch admin laptop atom1u

VLAN 3999 (uplink)

IP Host
DHCP atom1u
DHCP admin laptop

VLAN 4000 (auerswald)

IP Host admin laptop Auerswald Commander Basic2 atom1u

VLAN 4001 (PM3)

IP Host Livingston Portmaster 3 telnet/rlogin host (atom1u)
192.`68.3.222 admin laptop default-gw (atom1u) PPP lease pool

Updated by laforge 1 day ago · 12 revisions

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