IBM 3745 Maintenance Information Reference page 23

Configuration Flexibility: The interconnection between the FESL and the DMUX
or the SMUXA/B depends on the machine's configuration.
Any FESL card can be connected to any DMUX or SMUXA/B card.
See Figure 1-2 on page 1-6.
For more details on the transmission subsystem, see Chapter 4, "Transmission
Subsystem (TSS)."
Token-Ring Subsystem
The token-ring subsystem (TRSS) includes up to four token-ring adapters
(TRAs). The TRA is composed of one token-ring multiplexor card (TRM), and
two token-ring interface couplers (TICs).
The TRA occupies one CSP address position, and allows attaching two token-
rings via TIC cards.
Two types of TIC are available on the 3745:
• TIC type 1 (TIC1) attaches a token-ring operating at 4 Mbps only.
• TIC type 2 (TIC2) attaches a token-ring operating at 4 or 16 Mbps.
See Figure 1-2 on page 1-6.
If a TRA is not installed and there are line adapters (LA) following this missing
TRA, a bus propagation card BPC2 must be installed in the TRM's card unused
position.
For more details on the token-ring subsystem, see Chapter 5, "The Token-Ring
Subsystem. "
High Performance Transmission Subsystem
The high performance transmission subsystem (HPTSS) includes up to eight
high-speed scanners (HSS), also called line adapters (LA). One HSS is com-
posed of a communication scanner processor (CSP) and a front-end high-speed
scanner (FESH). The FESH interfaces with main storage via a DMA bus.
The HSS can be installed in all 3745 models in the ELA positions.
Lines cables are connected directly to the FESH card, via the tail gate.
See Figure 1-2 on page 1-6.
For more details on the high performance transmission subsystem, see
Chapter 6, "High Performance Transmission Subsystem (HPTSS)."
Ethernet Subsystem
The Ethernet subsystem (ESS) includes up to eight Ethernet LAN adapters
(ELA), also called line adapters (LA). One ELA is composed of a communi-
cation scanner processor (CSP) and an Ethernet adapter card (EAC). The EAC
interfaces with main storage via a DMA bus.
The ELA can be installed in all 3745 models in the HSS positions.
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IBM 3745 Maintenance Information Reference (MIR)