IBM 3745 Service Functions page 29

3745 Description
Short Description of the 3745
The IBM 3745 Communication Controller is composed of four main functional
units:
1. Controller subsystem (CSS)
2. Transmission subsystem (TSS)
3. Maintenance and operator subsystem (MOSS)
4. Power control card (PCC).
You may refer to "General Information" in the Hardware Maintenance Informa-
tion" for a description of the different models.
Controller Subsystem
The controller subsystem contains the CCU with its associated memory and
storage control (SCTL), the direct memory access (DMA), the DMA bus, the IOC
bus, and the channel adapter(s) with data streaming possibility.
Transmission Subsystem
MOSS
The transmission subsystem can contain the transmission subsystem (called
TSS), and/or a token-ring subsystem (TRSS), and/or a high-performance trans-
mission subsystem (HPTSS).
The TSS includes up to 6 low-speed scanners (LSS). Each LSS is composed of
one communication scanner card (CSC), which includes the functions of com-
munication scanner processor (CSP), and of a front-end low-speed scanner
(FESL). The line speed can be up to 256 kbps.
The HPTSS includes up to 2 high-speed scanners (HSS). Each HSS is com-
posed of a communication scanner processor (CSP) and of a front-end high-
speed scanner (FESH). The HSS is for lines with speeds of up to two millions
bps.
The TRSS contains up to 2 token-ring adapters (TRA). The TRA is composed of
a token-ring multiplexor card (TRM) and two tOken-ring interface couplers
(TICs).
The MOSS communicates with the CCU, and gives access to a disk, a diskette,
and the operator console. It also controls the enabling/disabling of CAs.
Power Control Subsystem
The power system is under the control of a microcoded
pce
card. The
pee
monitors the power system status and conditions; It also controls the power
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3745 Service Functions
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