• Code: B1
• Description: DIS/NSF that cannot be handled by the sender is received.
  The receiver received NSS/DCS other than those declared by DIS/NSF.
• Remedy: This may happen in some cases of bad line condition. Attempt the transmission again or ask the remote party to attempt the transmission again.

• Code: B2
• Description: DCN is received.
• Remedy: This may happen in some cases of bad line condition. Attempt the transmission again.

• Code: B3
• Description: DCS/DTC was not detected.
• Remedy: This may happen in some cases of bad line condition. Attempt the transmission again.

• Code: B4
• Description: The sender performed fall-back but the transmission was not enabled. The receiver performed time-out after sending FTT. Or DCN is received.
• Remedy: This may happen in some cases of bad line condition. Attempt the transmission again. Or ask the remote party to attempt the transmission again.

• Code: B5
• Description: CFR (FTT) was not detected.
• Remedy: This may happen in some cases of bad line condition. Attempt the transmission again.

• Code: C0
• Description: Image signal carrier was not detected.
• Remedy: This may happen in some cases of bad line condition. Ask the remote party to transmit again.

• Code: C1
• Description: High-speed signal was not detected on the receiving side.
• Remedy: This may happen in some cases of bad line condition. Ask the remote party to transmit again.

• Code: C2
• Description: After detecting the image signal, carrier off was detected for more than 1 second.
• Remedy: This may happen in some cases of bad line condition. Ask the remote party to transmit again.