User's Manual
V34bis Fax-modem - AJ 2885 P
AJ 2885 P - Page 34
•
transmission is controlled by RTS : &R2 or &R3 parameter
•
Transmission acknowledgement is provided by CTS : %C1 parameter
•
Carrier detection (remote modem signal) is provided by CD : &C1 parameter
Half duplex reversal delay :
this delay is set by the S26 register
•
expressed in Nx10 ms for connection without 75 BPS return channel (case 2 and 3 of the
previous picture) with a minimal value of 8 i.e. 80 ms
•
expressed in Nx1 ms for 1200/1200 full duplex connection (case 5 of the previous picture)
with a minimal value of 30, i.e. 30 ms. This mode applies on AJ2885P-Bxx models only.
The sending modem starts the S26 timer when the RTS signal rises, and sets the CTS signal
when the S26 timer is complete. This delay corresponds to the remote modem synchronization
time.
Bell 202 T
: Bell 202 specific frequencies are used thanks to the B1 command.
5.10. Saving user configurations
The
AJ 2885
modem can store up to 5 user configurations.
The AT&Wn command saves the current configuration in non-volatile memory (n = 0 to 4). This
configuration is saved even when the modem is turned off. The modem will load the last saved
user configuration at power-up.
5.11. V54 - Maintenance
The AJ 2885 modem provides V54 loop test functions.
The A terminal can monitor the following tests :
•
Analogue local loop or B3: the A modem connects on its own carrier. The A terminal can
check characters it sends are well returned. The good operation of the A modem is tested.
•
Remote digital loop or B2 : the B modem sends back all characters received from the line.
The A terminal can test the entire link to the remote modem.
A A B B
5.11.1. AT command operation
The status page 10 lists all V54 test features ( command AT&S10 )
♦
B 3 : local analogue loop
: the A modem is in local command mode. The local loop may
be started by the following commands :
♦
AT&T1 : simple loop. The modem connects and sends a CONNECT xxxx message. All
characters sent by the A terminal are sent back after modulation.
♦
AT&T8 : in the same kind of local loop the A modem sends and checks automatically test
characters. The error counter is displayed at the end of test.
♦
End of test : the test ends at the test timeout defined by S18, or by entering an escape
sequence ( '+++' )and an AT&T0 command
♦
Front panel LED: the CD led is on when the modem is connected, DSR led stays off.
♦
Example :
A A
