  We study error exponents for the problem of relaying a message over a tandem
of two channels sharing the same transition law, in particular moving beyond
the 1-bit setting studied in recent related works. Our main results show that
the 1-hop and 2-hop exponents coincide in both of the following settings: (i)
the number of messages is fixed, and the channel law satisfies a condition
called pairwise reversibility, or (ii) the channel is arbitrary, and a
zero-rate limit is taken from above. In addition, we provide various extensions
of our results that relax the assumptions of pairwise reversibility and/or the
two channels having identical transition laws, and we provide an example for
which the 2-hop exponent is strictly below the 1-hop exponent.
