Gestetner B003 Service Manual page 718

G4 to G3 fallback
Bit 0 of Communication Switch 07 must be at 0, or fallback from G4 to G3 will be
disabled.
The CPS codes for which fallback occurs are decided as follows.
• G4 bit switch 17, bit 7 - If set to "0", fallback occurs on receipt of a code from a
set that depends on the country code. If set to "1", fallback occurs for the 5 CPS
codes programmed in bits 0 to 6 of G4 bit switches 17, 18, 1A, 1B, and 1C, in
addition to the country code set.
Note that if G4 bit switch 18, bit 7 is set to "1", the CPS code set that is used is
always the Universal set, regardless of the country code setting.
G4 Internal Switch 19
No. FUNCTION
Permanence of the link
0 0: Set/released each LAPD call
1: Permanent
Channel used in ISDN L2 (64k)
1 mode
0: B1 1: B2
2-7 Not used
G4 Internal Switch 1A: CPS Code Used for G4 to G3 Fallback - 3
No. FUNCTION
Condition for fallback from G4 to G3
0-6
See the explanation for bits 0 to 6 of bit switch 17.
7 Not used
G4 Internal Switch 1B: CPS Code Used for G4 to G3 Fallback - 4
No. FUNCTION
Condition for fallback from G4 to G3
0-6
See the explanation for bits 0 to 6 of bit switch 17.
7 Not used
G4 Internal Switch 1C: CPS Code Used for G4 to G3 Fallback - 5
No. FUNCTION
Condition for fallback from G4 to G3
0-6
See the explanation for bits 0 to 6 of bit switch 17.
7 Not used
G4 Internal Switch 1D - Not used (do not change these settings)
G4 Internal Switch 1E - Not used (do not change these settings)
G4 Internal Switch 1F - Not used (do not change these settings)
SM
COMMENTS
Keep this at 1 in the USA. In other areas, this
bit is normally 0, depending on network
requirements.
When making an IDSN L2 back-to-back test,
you can select either the B1 or B2 channel
with this bit switch.
Do not change the factory settings.
COMMENTS
Do not change this setting.
COMMENTS
Do not change this setting.
COMMENTS
Do not change this setting.
3-61
BIT SWITCHES
B003/B004/B006/B007