Livingston PortMaster 3 » History » Revision 18

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DrDeke, 11/12/2023 01:29 PM
Add PM3-CMP board

Livingston Portmaster 3

laforge bought three Livingston Portmaster 3 PM3A-1E, which are RAS (Remote Access Server) that
  • terminates one 1E line (30 B-channels)
  • provides ISDN dial-up on those channels
  • provides DSP based modems in case analog modem calls should be handled.

One unit (rbbs-pm3) is part of the Dialup_Network_In_A_Box, another unit (pm3-2) is part of the Colocated_Hub, the third one is at @laforge's basement.


Electronics / Pictures

External pictures

Livingston_Portmaster3_front.jpg Livingston_Portmaster3_top.jpg Livingston_Portmaster3_back.jpg


Livingston_Portmaster3_mainboard.jpg Livingston_Portmaster3_mainboard2.jpg Livingston_Portmaster3_mainboard_top.jpg Livingston_Portmaster3_mainboard_bottom.jpg

DSP / Modem Board

There are 6 slots for modem boards, each board typically has 10 soft-modems, resulting in a total capacity of maximum 60 modems (equalling the number of B-channels in 2 E1 PRI links)

Livingston_Portmaster3_dsp_top.jpg Livingston_Portmaster3_dsp_bottom.jpg

PM3-CMP Stac Compression Board

There is a set of expansion headers on the mainboard which, according to the hardware installation guide, can accommodate a "compression or accelerator card". The compression card is model PM3-CMP and allows Stac compression to run on up to 60 channels.


Spare Parts / Mods


The original fan is a Fonsan DFB0812M (DC 12V 0.1A) fan by DELTA ELECTRONICS INC. The specs seem to state 2600 RPM / 24.8 dB(A) / 29 cfm.

I found it too noisy and replaced it with a Noctua NF-A8 FLX with L.N.A (reduced to 1650 rpm / 12.9 dB(A) / 24 cfm)

Fun fact: The PM3 actually seems to have a 5V -> 12V DC/DC upconverter just for the fan - instead of simply using a 5V fan...

Power Supply

One of the PM3A-E1 at laforge had a broken power supply. The oroginal PSU is an ASTEC LPS1112 rated for 5V/22A output (80W convection cooled, 1120W with 30cfm forced air).

It was replaced with a Mean Well LRS-150F-5. Mechanical assembly via a custom adapter plate that was fabricated easily from a small piece of aluminium sheet metal (175 x 102 mm) with a few drill holes.

PM3-PSU-1.jpg PM3-PSU-4.jpg PM3-PSU-2.jpg

Serial console cable

A null-modem cable can be built with the following pin-out:

DB-9 female (PC) DB-25 male (PM3) Suggested RJ45
1 20 1
2 2 2
3 3 3
4 8 4
5 7 5
6 - -
7 5 6
8 4 7
9 22 8


route to different telpnet hosts based on called party number

Assuming one wants to use a PM3 to act as modem bamk for accessing differnt [virtualized] BBSs over telnet, the problem is how to route the inbound call to a specific telnet IP address. The non-radius stand-alone configuration of the PM3 only permits either:
  • automatic forwarding of all calls to one global telnet/rlogin host
  • allowing the users to enter the hostname for telnet themselves
  • providing a list of pre-configured telnet desinations to all users (this was used at the 36C3 retronetowrking installation, see 36C3)

However, with the Call-Check radius feature, it should be possibl to receive the called + calling identity before the call is even accepted, and the nin return provide the telnet IP/port to which the call shall be routed.

Details in
  • Page 4-17 of the PM3A Radius for Unix manual
    • PM3A sends access-request with
      • User-Name=SETUP.Calling-Station-Id/No-Call-ID
      • Service-Type=Call-Check
      • Called-Station-Id=SETUP.Called-Station-Id
    • Radius sends response with
      • Login-IP-Host pointing to IP of telnet/rlogin
      • Login-Service=(Telnet,Rlogin,TCP-Clear)
      • Login-TCP-Port pointing to IP of telnet/rlogin
      • Service-Type=Login-User
  • Page 3-4 of the PortMaster Command Line Reference
    • set call-check on

Updated by DrDeke 8 months ago · 18 revisions

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