P300H
P300 Modem Installation and Operating Handbook
Page 174
Aux Port
Pin Number
Sync
Async
RS422 usage
RS 232 usage
26
8
Tx Aux Clock out A
Tx Aux Clock out
27
8
Tx Aux Clock out B
n/c
9
8
8
Tx Aux Data in A
Tx Aux Data in
10
8
8
Tx Aux Data in B
n/c
28
8
Rx Aux Clock out A
Rx Aux Clock out
29
8
Rx Aux Clock out B
n/c
11
8
8
Rx Aux Data out A
Rx Aux Data out
12
8
8
Rx Aux Data out B
n/c
42
(
8
)
Tx Aux Octet out A
Tx Aux Octet out
43
(
8
)
Tx Aux Octet out B
n/c
44
(
8
)
Rx Aux Octet out A
Rx Aux Octet out
45
(
8
)
Rx Aux Octet out B
n/c
50
8
8
Ground
Ground
(
8
) indicates lines are optional
In Closed Net Plus ESC mode the aux port is not used.
In IBS modes the Aux port can be set to both `INTELSAT` (using TS32 bit 1) and `Sync` modes (selectable
to use any of TS16, TS32 bits 1& 5-8, & TS48). In both modes a clock is provided and the port can be used
synchronously (with the clock), or asynchronously (allowing the async data to be oversampled by the
higher rate clock). In this oversampled mode (as specified by INTELSAT), the Baud rate is limited to
approximately 25-33% of the synchronous clock rate.
In IDR modes the Aux port provides either 32 or 64kbps data access in place of either one or both of the
32kbps ADPCM audio channels. Typically this would be used synchronously, but if required it could be
used asynchronously & oversampled giving maximum baud rates of approx 9600 Baud (in place of one
audio channel) or 19200 Baud (in place of both Audio channels).
