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CX900e Hardware Reference Manual
5-8
3006M100-002
5.2.3 DTE/DCE Interface Configuration
The V.35EU Serial I/O Card’s port can be configured either as a DTE or a DCE
device. The DCE/DTE strapping has been silk-screened on the I/O card to aid in
configuration.
DCE
When configured as a DCE device, the port transmits DCD, DSR and CTS and the
synchronous clock signals TXC and RXC. The port must receive DTR and RTS
from the attached DTE. Terminals, printers, controllers and hosts are always DTE
devices.
DTE
When configured as a DTE device, the port transmits DTR, RTS and ETXC and
receives DCD, DSR and CTS and the synchronous clock signals TXC and RXC
from the attached DCE.
A jumper bank socketed at U8 provides DTE/DCE configuration. Permanent
metal bands on the top surface of the jumper bank strap signals according to DCE/
DTE requirements. The orientation of the jumper bank determines whether the
port will be DTE or DCE. Rotating the jumper 180° changes the port from one
kind of device to the other, as illustrated below.
5.2.4 V.35EU Serial I/O Card Signal Handling
Signaling through the V.35EU Serial I/O Card’s port complies fully with the
ITU-T’s (CCITT) V.35 standard for an M-34 block connector.
Figure 5-6 V.35EU DTE/DCE Configuration Jumper
Table 5-2 Signal Pin-Outs for V.35EU Port
V.35EU
Signal
Circuit Function ITU-T
M-34
Pin No.
Signal
DTE
Direction-
DCE
F. GND Protective Ground 101 A n/a n/a
TXDA Transmitted Data (Set A) 103-A P Out In
RXDA Received Data (Set A) 104-A R In Out
RTS Request to Send 105 C Out In