Fresenius Medical Care 4008 E Technical Manual page 535

Keybox interface (connector X11)
An interface for the keybox (patient key interface) installed on P.C.B. LP763 is controlled by the
digital inputs and outputs of the SCC2698 (IC1). When the FINESSE system and the keybox is
connected, this interface is used to read the patient keys and to transfer the data via channel e to
the FINESSE system.
The key contents are read by a bit-serial process in a non RS232-compatible format. The yellow
LED in the keybox is activated via a digital output in conjunction with transistor T1.
CAN interface (connector X12)
The INTEL CAN controller 82527 (IC5) is used for data exchange with modules that themselves
have a CAN connection. The connections of the CAN bus are routed to the CAN bus A of the 4008
via a driver (Si9200 or 75LBC031, IC6). Transmission parameters are 500 kBaud for CAN V2.0b-
active-standard. The levels comply with the requirements of ISO 11898.
COMMCO-1 interface
To ensure compatibility the plug connections on P.C.B. LP763 for the connection of the COMM-
CO-I board were not changed.
Connector assignment:
Conn. Connection to
X1 X1 on P.C.B. LP 729 (COMMCO-1)
X10 X4 on P.C.B. LP 729 (COMMCO-1)
X14 X1 on P.C.B. LP 751 (decoupled for FINESSE interface of COMMCO-1)
BTM interface (connector X13)
To permit connection of a BTM module in dialysis machines with software 4.0 or higher (without
using a COMMCO board), a BTM interface has been integrated on P.C.B. LP 763. The major
parts of this interface are a programmable PLD (lattice ispLSI1016, IC11), several driver gates
(IC10) and a driver transistor (T2) with circuitry.
The function of the BTM interface is to ensure bidirectional communication between the dialysis
machine and the BTM module.
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Fresenius Medical Care 4008 4/09.03 (TM)