PC Network

@EFEF.ADF IBM PC Network Adapter (Both Baseband and Broadband)

187-082 IBM PC Network Baseband Adapter/A (Wrap Plugs)
187-080 IBM PC Network Adapter II/A (Coax)
187-219 IBM PC Network Adapter II/A-Frequency 2 and 3 (Coax)

PC Network Baseband Adapter
PC Network Broadband Adapter
Known Problems
ADF Sections


PC Network Baseband Adapter

H 36 position edgecard socket
J1 RJ11 Terminator
J2 RJ11 Wrap
T1 PE-64570
T Terminator Plug
W Wrap Plug
Y2 16.00000 MHz osc
ZM2 M5M5179P-45 RPL
ZM4 25F8241
ZM5 74F7673

PC Network Baseband Network Layout (from William R. Walsh)

It is a "baseband" adapter, whatever that means. Standard RJ11 phone cable and connectors were used to connect the adapters together, and to a "hub" of sorts. The adapters were not only attached to each other (a bus topology), but each "bus" was connected at a central hub, creating a series of connected "subnetworks" at the point of the hub.

As for the purpose of T and W plugs, W is identified as being a "Wrap Plug" in my manual, and "T" as a terminator plug. The T plugs were plugged into the second jack of the last adapter on a "line". If you took the "T" plug out of the adapter, the whole line of computers failed to work (like a string of XMAS lights), but other computers on other "subnetworks" would still work. As for the "W" plug, it was put into any of the unused ports on the hub. If it was taken out, the hub would fail to work at all. Also, the hub did not allow communication between clients on two (or more) different "subnetworks" attached to it. This made it necessary to have at least one computer that had a printer on each "subnetwork". The server (if any was used) went into its own special port on the "hub" that could communicate with any of the other connected "subnetworks".

As for the insides of the "T" and "W" plugs, it looks like there is some kind of resistor in the "T" (clear) plug. The "W" plug has something in it, but I don't know what it is. Too dark brown to tell for sure.

The Baseband adapter supports daisy chain as well as star topologies via the IBM 5173 PC Network Baseband Extender announced today in IBM Product Announcement 187-083. Up to eight workstations can be linked together in a chain topology with an overall length of up to 200 feet of 4-wire twisted pair IBM Cabling System Type 3 specification telephone wire. A chain of workstations linked to the 5173 can have an overall length of up to 400 feet. Up to ten daisy chains with eight workstations each can connect to the Baseband Extender for a maximum of 80 workstations in the baseband IBM PC Network.


Serial Connection of Baseband Adapters

"W" plug -- Machine 1 -- "T port" -- "W" port -- Machine 2 -- "T" plug. If using a 5173, the T plug should be on the card farthest from the 5173. The W plug should be in either one of the 5173's OUT ports.

Think of it like terminating a SCSI chain. Up to eight systems can be serially connected.

Maximum Distance from First to Last Nodes

# Nodes      Max Distance
  2          91.4m (300 ft)
  3          83.8m (276 ft)
  4          76.0m (250 ft)
5 or 6       68.5m (225 ft)
7 or 8       61.0m (200 ft)

IBM PC Network Broadband

IBM's broadband PC Network addresses the specialized requirements of customers who are combining their LAN with other services, such as video, voice, security and/or additional data channels on a common broadband medium. It may also be used to meet the requirements of small businesses and individual work groups.

IBM PC NETWORK ADAPTER II: The IBM PC Network Adapter II is a feature card for connecting the new IBM Personal System/2 Model 30 and IBM Personal Computers to the broadband IBM PC Network. It is compatible with the form factor and bus design of the original Personal Computer, yet it is designed to take advantage of greater Intel 80286 and 8086 processing speeds.

The IBM PC Network Adapter II supports the NETBIOS interface and the 802.2/Logical Link Control (LLC) protocols via the IBM LAN Support Program which was also announced today. This allows the adapter to provide access to IBM PC Network and IBM Token-Ring Network applications written to the NETBIOS or APPC/PC interfaces.

The IBM PC Network Adapter II is also compatible with the protocols of the original PC Network Adapter via the IBM PC Network Protocol Driver program which was also announced today. This allows the adapter to take advantage of the same protocol and interface as the original IBM PC Network. See IBM Product Announcement 187-079, dated April 2, 1987, for details.

IBM PC Network Adapter II/A

The IBM PC Network Adapter II /A is a feature card specifically designed for connecting the new IBM Personal System/2 Model 50, Model 60, Model 80-041, and Model 80-071 computers to the broadband IBM PC Network. It is compatible with the form factor and bus design of these new Personal System/2s to take advantage of greater Intel 80286 and 80386 processing speeds.

The IBM PC Network Adapter II/A supports the NETBIOS interface and the 802.2/LLC protocols via the IBM LAN Support Program which was also announced today. This allows the adapter to provide access to IBM PC Network and IBM Token-Ring Network applications written to the NETBIOS or APPC/PC interfaces.

The IBM PC Network Adapter II/A is also compatible with the protocols of the original IBM PC Network Adapter via the IBM PC Network Protocol Driver program which was also announced today. This allows the adapter to take advantage of the same protocol and interface as the original IBM PC Network.

The IBM PC Network Adapter II/A is not designed for use in the IBM Personal System/2 Model 30. See IBM Product Announcement 187-080, dated April 2, 1987, for details.


Channel usage, frequencies, offsets, and splits

Adapter TX Channel RX Channel Offset Split
PC Ntwk Adt,II, II/A T14 (47.75-53.75) J (216-222) 168.25 Mid Only
PC Ntwk Adt II/A -Freq 2 2' (53.75-59.75) O (246-252) 192.25 Mid/High
PC Ntwk Adt II/A -Freq 3 3' (59.75-65.75) P (252-258) 192.25 Mid/High


PC Network Broadband Adapter

H 36 position edgecard socket
K1,2 Kyocera 39.5M L
K3 Kyocera 50MA
U1 Intel D82588
U2 Hitachi HM6264LP-12
U3 SLA6270J1B (62X0870)
U8 72X8139
Y1 16.0 NDK.8741 xtal
Y2 KXN 6321 xtal

I have a similar card that has the module used in the broadband adapter above. Possibly this card/module combination could be used as a baseband or broadband with the swapping of the module. The slot cover and module are attached to the base card with two screws. To swap the module, you unscrew both screws on the back of the base card and then screw on the new module after plugging it in the socket.


Broadband Adapter Compatibility

Direct communication between PC Network adapters is possible only when each adapter uses the same RF channels and the same protocols. The PC Network Adapters (original, II, and II/A), the IBM PC NETWORK ADAPTER II/A - FREQUENCY 2 and the IBM PC NETWORK ADAPTER II/A - FREQUENCY 3 cannot communicate directly with each other. For communication between different RF channel pairs, bridging is required. Broadband PC Network adapters can communicate with each other according to the table below:

| # |  =   Direct communication supported when both adapters
           are  using PC LAN Support Program (802.2 protocols).
|   |  =   Bridging required for communication.
                                1   2   3   4    5    6   7
                               |---+---+---+---+---+---+---|
- IBM PC Network Adapter       | # | # | # |   |   |   |   |
                               |---+---+---+---+---+---+---|
- IBM PC Network Adapter II    | # | # | # |   |   |   |   |
                               |---+---+---+---+---+---+---|
- IBM PC Network Adapter II/A  | # | # | # |   |   |   |   |
                               |---+---+---+---+---+---+---|
- IBM PC NETWORK               |   |   |   |   |   |   |   |
  ADAPTER II - FREQUENCY 2     |   |   |   | # | # |   |   |
                               |---------------------------|
- IBM PC NETWORK               |   |   |   |   |   |   |   |
  ADAPTER II/A - FREQUENCY 2   |   |   |   | # | # |   |   |
                               |---+---+---+---+---+---+---|
- IBM PC NETWORK               |   |   |   |   |   |   |   |
  ADAPTER II - FREQUENCY 3     |   |   |   |   |   | # | # |
                               |---+---+---+---+---+---+---|
- IBM PC NETWORK               |   |   |   |   |   |   |   |
  ADAPTER II/A - FREQUENCY 3   |   |   |   |   |   | # | # |
                               |---+---+---+---+---+---+---|

Note: Adapters that use unlike protocols can coexist with each other on the same coaxial cable, but will not be able to communicate with each other.
   The 5178 IBM PC Network Translator Unit is not compatible with the frequencies used by the IBM PC NETWORK ADAPTER II/A - FREQUENCY 2 and the IBM PC NETWORK ADAPTER II/A - FREQUENCY 3. A vendor translator is required.


Known Problems

PS/2 Adapter Installation Restrictions 3270, Token Ring, Etc. (H005662)


AdapterId EFEF "PC Network Adapter "

Type, Memory Location, Interrupt Level
 The three adapter types are: primary, alternate and Remote Program Load (RPL).  The three memory locations are MEM 1, MEM 2, or MEM 3.  When you specify the interrupt levels for the adapter, if it is primary or RPL, use INT 2 or INT 3.  If it is alternate, use INT 3.
     <"Primary, Mem 1, Int 2" (620-627, int 2, C800-CFFF)>, "Mem 2, Int 2" (620-627, Int2, D000-D7FF), "Mem 3, Int 2" (620-627, Int2, D800-DFFF),  "Mem 1, Int 3" (620-627, Int3, C800-CFFF), "Mem 2, Int 3" (620-627, Int3, D000-D7FF), "Mem 3, Int 3" (620-627, Int3, D800-DFFF)
    "Alternate, Mem 1, Int 3" (628-62F, Int3, CE00-CFFF), "Mem 2, Int 3" (628-62F, Int3, D600-D7FF), "Mem 3, Int 3" (628-62F, Int3, DE00-DFFF)
     "RPL, Mem 1, Int 2" (620-627, Int2, C800-CFFF), "Mem 2, Int 2" (620-627, Int2, D000-D7FF), "Mem 3, Int 2" (620-627, Int2, D800-DFFF), "Mem 1, Int 3" (620-627, Int3, C800-CFFF), "Mem 2, Int 3" (620-627, Int3, D000-D7FF), "Mem 3, Int 3" (620-627, Int3, D800-DFFF)

Content created and/or collected by:
Louis Ohland, Peter Wendt, David Beem, William Walsh, Tatsuo Sunagawa, Jim Shorney, Tim Clarke, Kevin Bowling, Tomáš Slavotínek, and many others.

Ardent Tool of Capitalism - MAD Edition! is maintained by Tomáš Slavotínek.
Last update: 29 Jun 2022 - Changes & Credits | Legal Info & Contact