Service manual

B-4 Sun Ultra 2 Series Service Manual • July 1996
7 Gnd Signal Ground.
8 DCD I Data carrier detect. Used by the DCE
to indicate it is receiving a suitable
signal from the communications
channel.
9 - 14 Not connected none None.
15 TRXC I Transmit clock. Used by the DCE to
providetiming information to the DTE.
The DTE provides data on TXD in
which the transition of the bit
corresponds to the rising edge of the
clock.
16 Not connected none None.
17 RTXC I Receive clock. Used by the DCE to
providetiming information to the DTE.
The falling edge of the clock
corresponds to the center of the data
bit received on RXD.
18 -19 Not connected None.
20 DTR O Data terminal ready. Used to control
switching of the DCE to the
communication channel. Once
disabled, DTR cannot be enabled until
SYNC is turned OFF.
21 - 23 Not connected None.
24 TXC O Terminal clock. Generated by the DTE
to provide timing information to the
DCE. Used only in Synchronous mode
and only when the driver requests a
locally generated clock. Otherwise,
TXC echoes the modem-generated
clock. The falling edge of the clock
corresponds to the center of the data
bit transmitted on TXD.
25 Not connected None.
TABLE B-2 Serial Port A and B Connectors Pin Assignments (Continued)
Pin Signal Name I/O Description