0049-1200-XXX RM16M – USER’S GUIDE 12/29/2010
Rev. C
Page 19
of
27
Pin No.
EIA-232C
CCITT
Signal Name
Description
14
SBA
141
Sec. Transmit Data
Transmitted data on a secondary channel.
15 DB
Transmit
Clock
(DCE)
A transmit data clock output for use by an
external data source. Positive clock
transitions correspond to data transitions.
16
SSB
Sec. Rec’d. Data
Received data on a secondary channel.
17
DD
115
Receive Clock
A receive data rate clock output for use by
the external data sink. Positive clock
transitions correspond to data transition.
18
Not
used.
19
SCA
140
Sec. Request to
Send
Request to send on a secondary channel.
20 CD 108.2
Data
Terminal
Ready
This circuit is positive when the DTE is
ready to originate or answer a call in dial
up operation.
21 SQ 110
Signal
Quality
Indicator
Signals on this circuit are used to indicate
the probability of an error in the received
data. A positive level indicates good
signal quality while a negative level
indicates poor signal quality.
22
CE
125
Ring Indicator
In direct dial operation, this circuit is
positive in response to an incoming ring
signal.
23
CH
111
Data Rate Select
Supplies a data rate control to select
Primary or Fallback data rate.
24 DA 113
External
Transmit
Clock
A serial data rate clock input from the data
source. Positive clock transitions
correspond to data transitions.
25
Not
used.
