OpenVox G400E - increase incoming volume from GSM?

; Span 2: opvxg4xx/0/1 "OpenVox G400P GSM/CDMA PCI Card 0" 
group=12
context=from-gsm
signalling = gsm
smscodec=utf-8
debugat=on
;tty=off
anonymouscall=off
;atz_timeout=5
;vol=
;mic=
;band=
;dialprefix=
;pin=1234
channel => 9
context = default
group = 63

; Span 3: opvxg4xx/0/2 "OpenVox G400P GSM/CDMA PCI Card 0" 
group=13
context=from-gsm
signalling = gsm
smscodec=utf-8
debugat=on
;tty=off
anonymouscall=off
;atz_timeout=5
;vol=
;mic=
;band=
;dialprefix=
;pin=1234
channel => 11
context = default
group = 63

; Span 4: opvxg4xx/0/3 "OpenVox G400P GSM/CDMA PCI Card 0" 
group=14
context=from-gsm
signalling = gsm
smscodec=utf-8
debugat=on
;tty=off
anonymouscall=off
;atz_timeout=5
;vol=
;mic=
;band=
;dialprefix=
;pin=1234
channel => 13
context = default
group = 63

; Span 5: opvxg4xx/0/4 "OpenVox G400P GSM/CDMA PCI Card 0" 
group=15
context=from-gsm
signalling = gsm
smscodec=utf-8
debugat=on
;tty=off
anonymouscall=off
;atz_timeout=5
;vol=
;mic=
;band=
;dialprefix=
;pin=1234
channel => 15
context = default
group = 63

 Kernel
   Linux(i386)-2.6.18-406.el5

 Elastix
   elastix-2.5.0-1
   elastix-a2billing-1.9.4-7
   elastix-a2billing-callback_daemon-1.9.4-7
   elastix-addons-2.5.0-3
   elastix-agenda-2.5.0-1
   elastix-asterisk-sounds-1.2.3-1
   elastix-email_admin-2.5.0-1
   elastix-endpointconfig2-2.5.0-1
   elastix-extras-2.5.0-1
   elastix-fax-2.5.0-1
   elastix-firstboot-2.5.0-1
   elastix-framework-2.5.0-2
   elastix-im-2.5.0-1
   elastix-my_extension-2.5.0-1
   elastix-pbx-2.5.0-1
   elastix-portknock-0.0.1-0
   elastix-reports-2.5.0-1
   elastix-security-2.5.0-1
   elastix-sugarcrm-addon-5.2.0l-9
   elastix-system-2.5.0-1

 RoundCubeMail
   RoundCubeMail-0.3.1-12

 Mail
   postfix-2.3.3-7.el5
   cyrus-imapd-2.3.7-16.el5_11

 IM
   openfire-3.7.1-1

 FreePBX
   freePBX-2.11.0-19

 Asterisk
   asterisk-11.17.1-1
   asterisk-perl-1.03-0
   asterisk-addons-11.17.1-1

 FAX
   hylafax-4.3.11-1rhel5
   iaxmodem-1.2.0-2

 DRIVERS
   dahdi-2.10.0.1-3
   rhino-0.99.6-4.b4
   wanpipe-util-7.0.12-3

; You may also set the default receive and transmit gains (in dB)
;
; Gain Settings: increasing / decreasing the volume level on a channel.
;                The values are in db (decibells). A positive number
;                increases the volume level on a channel, and a
;                negavive value decreases volume level.
;
;                There are several independent gain settings:
;   rxgain: gain for the rx (receive - into Asterisk) channel. Default: 0.0
;   txgain: gain for the tx (transmit - out of Asterisk Asterisk) channel. 
;           Default: 0.0
;   cid_rxgain: set the gain just for the caller ID sounds Asterisk
;               emits. Default: 5.0 .

rxgain=5.0
txgain=5.0