S Registers 51
S74 V.80 Synchronous Access Mode Sub-parameters. Nonstorable.
Bits 1-0. Character transmitted on idle in transmit mode
■ 00 Transmit 8 bits SYN. the receiver does not hunt for synchronization
sequence.
■ 01 Transmit 8 bits SYN. the receiver hunt for 8 bits SYN sequence.
■ 10 Transmit 16 bits SYN. the receiver hunt for 16 bits SYN sequence.
Bit 2. Character transmitted on idle in framed mode
■ 0 Transmit HDLC flags
■ 1 Transmit marks
Bit 3. Character transmitted on underrun in framed mode
■ 0 Transmit abort
■ 1 Transmit flag
Bit 4. Half duplex option (not used)
Bits 6-5. CRC type
■ 00 CRC generation and checking disabled
■ 01 Use 16 bits CRC
■ 10 Use 32 bits CRC
■ 11 not used
Bit 7. NRZI encoding
S75 V.80 Synchronization Sequence (first byte). Synchronization sequence used while
in synchronous access mode.When using 16 bits SYN, this register represent the
first 8 bits. Nonstorable. Default is 256
S76 V.80 Synchronization Sequence (second byte). Last 8 bits of a 16 bits SYN
sequence. Nonstorable. Default is 256.
S77 Report period of the nb of octets in rx buffer. Nonstorable. Default is 256.
S78 Bits 7-6. V.42 Dictionary size (V25ter only). Nonstorable. Default is 256.
00 512 characters
■ 10 2048 characters
■ 01 1024 characters
■ 11 Maximum dictionary size characters
Bits 5-0. Max coded string length (V25ter only) 6 to 64, other value reserved.
