P300H P300 Series Modem Installation and Operating Handbook Page 186
Aux Port
Pin Number Sync Async RS422 usage RS 232 usage
26 Tx Aux Clock out A Tx Aux Clock out
27 Tx Aux Clock out B n/c
9Tx Aux Data in A T x Aux Data in
10 Tx Aux Data in B n/c
28 Rx Aux Clock out A Rx Aux Clock out
29 Rx Aux Clock out B n/c
11 Rx Aux Data out A Rx Aux Data out
12 Rx Aux Data out B n/c
42 ( ) Tx Aux Octet out A Tx Aux Octet out
43 ( ) Tx Aux Octet out B n/c
44 ( ) Rx Aux Octet out A Rx Aux Octet out
45 ( ) Rx Aux Octet out B n/c
50 Ground Ground
() 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 an y o f TS 1 6, TS32 bits 1& 5 - 8, & TS48). I n b o t h modes a clock is provided and the port can be used
synchronously (with the clock), or asy nchronously (allowi ng the async data to be oversam pled by the higher
rate clock). In this oversampled mode (as specified by I NTELS AT), the Baud rate is limited to approx imately
25-33% of the synchronous clock rate.
In IDR modes the Aux port provides eit her 32 or 64kbps data access in place of either one or both of the
32kbps ADPCM audio channels. Typically thi s w ould be used sy nchronous ly, but if required it could be used
asynchronously & oversampled giving maximum baud rates of approx 9600 B aud (in place of one audio
channel) or 19200 Baud (in place of both Audio channels).